FLIES. 423 



fond of salt or brackish water; still others prefer dry situations, and are found on 

 stumps of trees, fences, etc., even in very dry and hot weather " (Zoew). The proboscis 

 is short, and not so well adapted for piercing hard insects as in the Asilidae and 

 Empidse. As in the latter family, the legs often present ornamental and structural 

 characters, many of which may serve for grasping and holding their prey. About 

 twelve hundred species are known throughout the world. 



Sub-Oedee II. — Cycloehapha. 



LarvaB without a differentiated head, the first segment never chitinous, with soft, 

 wart-like antennae, or wholly without appendage, showing only a mouth opening. 

 Body cylindrical or flattened, smooth, or with swellings for locomotion, or with girdles 

 of short bristles, sometimes with thread-like filaments. The larvae shed their skins 

 twice or thrice before assuming the pupal stage, escaping through a rent at the pos- 

 terior end. Pupae always enclosed in the contracted larval skin, the adult insect 

 escaping through a circular orifice at the anterior end. Adult insects with an arcuated 

 impressed line, immediately above the antennae, separating a small crescentric piece, 

 the frontal lunule. • 



Brauer accepts two sections in this sub-order, viz., Aschiza, with the families of 

 Syrphidae, Platypezidae, Phoridte, and Pipunculidse, and Schizophora with all the other 

 families. 



The Stephid^ may be at once distinguished with certainty in nearly every case 

 by a peculiarity of neuration. Between the third and fourth longitudinal veins, and 

 nearly parallel with them, there is a spurious or false vein, of greater or less extent 

 and distinctness. The antennae in nearly all have a bristle on the upper border of the 

 third and last joint ; in a few there is a terminal style. The eyes are usually contig- 

 uous above in the male, and they are sometimes provided with enlarged facets in this 

 sex; sometimes in both they are jsrettily ornamented with colored- markings. In 

 coloration the flies are generally very conspicuous, and often strikingly handsome; 

 consisting of bright yellow spots and bands on black or green, often metallic ground. 



In size they are seldom very large or small ; but in shape they present the utmost 

 diversity. In Volucella evecta, a species not uncommon throughout the United States, 

 the body is nearly the size of a humble-bee, and very much like some of them in 

 appearance. It is thickly clothed with long black and yellow pile, the antenna 

 are elongate, and the bristle of the third joint is very thickly plumose feathery-like. 

 Most curiously too, European species, distinguishable with difficulty from this, are 

 parasitic in the larval state upon the young of humble-bees. The larva of V. bomby- 

 lans has along each side two rows of short spines, with six longer ones radiating fi'om 

 the thickened and rounded posterior end. Undoubtedly the larva of V. evecta will be 

 found to be similar, and with similar habits. 



A very interesting species is Eristalis tenax, probably first an European species, 

 but which has become now almost cosmopolitan. It is rather larger than a honey-bee, 

 which it resembles so much that few persons not acquainted with it would care to 

 touch it. Like all the members of this family, it lives upon the juices of flowers, 

 especially sweet-smelling ones such as Hymenoptera prefer, but it most commonly 

 attracts our attention by its appearance in houses on windows late in the autumn. 

 Although so conspicuous an insect, the earliest record we have of it in America 

 dates no further back than 1870 ; at present it is common from the Atlantic to the 



