494 DIPTERA CHAP. 



The males are reiiiarkalile for the curious special characters they 

 possess on the feet, antennae, face, or wings. These characters 

 are not alike in any two species ; they are believed to be of the 

 nature of ornaments, and according to Professor Aldrich and others 

 are used as such in courtship.^ This family of flies approaches 

 very closely to some of the Acalyptrate Muscidae in its char- 

 acters. It is united by Brauer with Empidae to form the tribe 

 Orthogenya. Although the species are so numerous and 

 abundant in Europe, little is known as to their metamorphoses. 

 Some of the larvae frequent trees, living under the bark or in 

 the overflowing sap, and are believed to be carnivorous ; they are 

 amphipneustic ; a cocoon is formed, and the pupa is remark- 

 able on account of the existence of two long horns, bearing the 

 spiracles, on the back of the thorax ; the seven pairs of abdominal 

 spiracles being excessively minute.'^ 



Series 3. Cyclorrhapha Aschiza 



Fam. 28. Phoridae. — SmoII flies, 'witlt very eonrcx thorax, 

 small head, very small two-jointecl antennae, l)earing a long seta ; 

 feynora more or less broad; wings ivith two dark, thick, a2)proxi- 

 inate veins, riieeting on the front margin near its middle, and 

 besides these, three or four very fine veins, tluit ran to the margins 

 in a siih-jMrcdlel manner without forming any cells or forks. This 

 obscure family of flies is of small extent, but its members are ex- 

 tremely common in Europe and North 



r T" -^^ America, where they often occur in 



\^\Z^ — ^^i-^--^l1\ numbers running on the windows of 



^^^~--<;CL_____^-^ houses. It is one of the most isolated 



Fig. 236.— Wing of Trincvm groups of Diptcra, and great difference 



(iierrima, one of the Phor- ,jf opinion prevails as to its classifica- 



idae. Britain. -mi • , ■ ■ ^■ 



tion. Ihe wmg-nervuration is peculiar 

 (but varies somewhat in the species), the total absence of 

 any cross -veins even on the basal part of the wing being- 

 remarkable. There are bristles on the head and thorax, but 

 they are not arranged in a regular manner. The larvae 

 live in a great ^'ariety of animal and vegetable decaying matter, 



^ Amcr. Katural. xxviii. 1894, p. 35. 



- Perris, Ann. Sue. ent. France (4) x. 1870, p. 321, pil. 4 ; and Labonlbene, oj). 

 cit. (5) iii. 1873, p. 50, pi. v. 



