90 ENTOMOLOGICAL SOCIETY 



character might be of some service here. Haliday drew atten 

 tion to the transverse suture of the thorax, which he believed 

 to be usually of the same depth through its whole extent in 

 the Calyptratce, but generally distinct at each side and imper 

 ceptible in the middle of the thorax in the Acalyptratce (L,cew, 

 Mon., I, p. 33). This character, likewise, can not be relied 

 upon. Similar difficulties arise in the separation of these flies 

 into groups or families. Distinguishing characters are not so 

 apparent here as in other families, nor are the characters most 

 to be relied upon so constant. It is therefore difficult to arrive 

 at a just decision concerning the location of some forms, until 

 one becomes familiar with the genera. The best plan to follow 

 in all doubtful cases is that of comparing the specimen with 

 generic descriptions until its affinities are clearly ascertained. 



I have followed Brauer and von Bergenstamm's work (to be 

 presently noticed) in the inclusion of the CEstridce with the 

 Calyptrate Musddcz. This scheme is not original with these 

 authors. Lcew expressed this idea in 1862 (1. c.). The 

 CEstridce have always been recognized, especially so in more 

 recent years, as possessing many characters in common with 

 the Musddce. Their rudimentary proboscis is about the only 

 character upon which they can be isolated. Their pilosity, 

 though not seen in the calyptratce, is paralleled in the 

 acalyptratce (Cordyluridce) . They possess its Muscid facies, the 

 same venation, the undeveloped empodia, and the dorsal never 

 terminal arista. The question of their parasitism naturally 

 links them with the calyptrate Muscidtz, the first five families of 

 which are, without exception, parasitic in their habits ; while 

 the infliction of this parasitism on the higher animals, and 

 even man, is analogous to the pseudo-parasitism of Comp- 

 somyia, and the true parasitism of Sarcophaga on Reptilia. In 

 this connection it should be noticed that Ctenostylum (^CEstridce} 

 has the tegulae very small, almost wanting ; this fact, however, 

 does not invalidate the present conception of the family, as all 

 the other genera possess usually large, but sometimes smaller 

 ciliate, tegulae. I can see no reason why the Q^stridce should 

 not be admitted into the Calyptrate Musddce as a sub-section on 

 an equality with the Creophilce, AnthophilcE, etc., and for 

 which the term Mammophiltz might be proposed. The 

 Tachinidce sens. lat. may also very appropriately constitute a 

 separate sub-section, distinguished from the Creophil<z (as thus 

 restricted) by the absence of hair on the arista, and for which 

 I coin the name Entomophilce. This gives us four natural, 

 and nearly equal, sub-divisions of the Calyptrate. 



The super-family MUSCINA, then (understood to embrace all 

 the Musddce sens, lat., including the CEstiidd], may be known 



