Cedar Creek
Ecosystem Science Reserve


Insects of Cedar Creek

Order DIPTERA

Family SYRPHIDAE

(Hover Flies)

(Table of Species)

The Flower Flies (874 NA spp) are a ubiquitous and conspicuous element of all Cedar Creek habitats. Most are patterned in yellow and black and hover at flowers. The larvae of some (eg. Syrphus, Metasyrphus) are aphid predators while others occur in shallow stagant waters (eg. the rat-tailed maggot of Eristalis tenax), and still others (Microdon spp) are scavengers in ant nests.

Roughly 80 species have been collected at Cedar Creek. They will be considered by Subfamily.

MICRODONTINAE
Species of Microdon (tristis, pseudoglobosus) resemble robust Tachinids. Their oatmeal shaped larvae are reported to be scavengers in ant mounds, and one can occasionally see adults hovering over the large thatch mounds of Formica obscuripes. Mixogaster sp. is a slender black-and-yellow banded species that is fairly common in prairies in late summer.

SYRPHINAE
The larvae of this Subfamily are primarily aphid predators.  Adults have bare humeri (postpronotal lobes), though these are often hidden by the concave posterior of their close fitting heads.  Genera with entirely black faces include Platycheirus (angustatus, immarginatus, quadratus, scambus), Pyrophaena rosarum?, and Melanostoma pictipes.  Species of Platycheirus have flattened fore-tarsi.  They are common at flowers in old fields. The remaining species in this Subfamily have some yellow on the face.  Those with an entirely black thorax include short, stubby species of Paragus (bicolor, tibialis) with pilose eyes, and the elongate Baccha fascipennis.  Species of Chrysotoxum (minor, fasciolatus) have elongate antennae and yellow striping on the abdomen.  More typical Syrphinae are  glabrous with yellow laterally on the thorax as well as on the abdomen. These include the common aphid predators with margined abdomens: Syrphus spp (bigelowi, knabi, rectus, ribesii, torvus, vitripennis), Metasyrphus spp (amalopsis, latifasciata, medius, wiedemanni), Eupeodes volucris, Epistrophe fischeri... Many of the common species occuring on flowers in old fields are in this group. In decreasing abundance they include: Mesograpta marginata?, Sphaerophoriaspp (xxx),  Toxomerus geminatus, Allograpta obliqua and Xanthogramma flavipes.

ERISTALINAE
Members of this Subfamily have pilose humeri.  The larvae of most feed on decaying organic debris in moist, sometimes shallow aquatic environments. Several Tribes are represented at Cedar Creek.
Sericomyiini.  Species with plumose antennae include Sericomyia (militaris, chrysotoxum) and Condidea lata.

Eristalini. A distinct group of generally common species having a cup-shaped vein at the apex of the wing and black setulae at the base of the hind femur.  Members include yellow and black striped species of Helophilus (fasciatus, hybridus, latifrons), pollinose species of Parhelophilus (rex, laetus, obsoletus), blue and gray marked beaky species of Lejops (=Lejota: bilineatus, lunulatus, relictus, stipatus), and often hairy species of Eristalis (tenax, nemorum, latifrons, dimidiatus, bastardi, barda, anthophorinus, flavipes). Species of Mallota (cimbiciformis, posticata) have enormous hind femora and resemble Bumblebees.  Species of Parhelophilus and Lejops are frequently common on Marsh Marigold (Caltha palustris).  Species of Eristalis and Helophilus frequent the fragrant blooms of Prunus, Amelanchier, and Rubus.

Brachyopini, Pipizini, Rhingiini.  This set of Tribes has the rm X-vein intersecting the discal cell before the middle.  The first mentioned have bare eyes.  Neoascia globosa and Sphegina flavimana are small brownish species with a constricted waist. They are sometimes common on Marsh Marigold (Caltha palustris). Rhingia nasica has a projecting snout while Myolepta sp has no snout and short antennae.  Species of Chrysogaster (nitida, pictipennis) and Orthnevra sp are dark brassy species that are fairly common.  Cartosyrphus tristis is black with a rugose forehead.  The remainder have pilose eyes and constitute an infrequently collected,  taxonomically confusing group.  They include species of Cheilosia, Ferdinandea, Heryngia, Pipizella and Cnemodon.

Cerioidini Milesiini.  Members of this Group have the rm X-vein intersecting the discal cell at or beyond the middle. Many members resemble wasps (elongate, black bodied with yellow pollinose bands on the abdomen) and are routinely found at flowers (esp. dogwoods, plum, and sumac). Species falling into this category include: Ceriana abbreviata, Somula decora, Sphecomyia quadrivittata, Spilomyia longicornis, and Temnostoma spp (alternans, barberi).  Criorhina verbosa resembles a Bumblebee.  Non-mimetic species in this group include: Syritta pipiens (with swollen and toothed hind femora), hairy species of Cynorhina (=Blera: analis, confusa) as well as Brachypalpus oarusTropidia quadrata has a large tooth on  its hind femur.  Species of  Xylota (angustiventris, ejuncida, nemorus, pigra, tuberculata, vecors) are black with spinose hind femora and are common to abundant on Marsh Marigold (Caltha palustris).
 
 


webmaster@cedarcreek.umn.edu Last updated May, 2000