28 



This classificjitiou looks very nice on pai^er, but when we under- 

 take to ai)i)ly it to the specinieus themselves, then the difficulty arises. 

 In the first ])la('e, in many species the macrochu'ta' are so reduced in 

 size that it is no easy matter to decide as to whether they should be 

 considered as macrocha^ta; or simply as bristly hairs. Then again, the 

 males of several species have five visible abdominal segments, while 

 their females have only four; and, conversely, the females of a few 

 si)ecies have five and their males only four. This difference is due to 

 the greater or less development of what, in those with only four abdom- 

 inal segments, is the first segment of the genitalia, and as this varies 

 in size in the different species, it is not always easy to decide as to 

 whether to regard it as belonging to the genitalia or as forming a dis- 

 tinct abdominal segment. In at least one genus (llemyda), the fourth 

 al)doininal segment is so reduced in size as to ajipear as a part of the 

 genitalia, and thus there are apparently only three abdominal segments. 

 These differences, therefore, are developmental rather than structural. 

 If there were differences in habits between these subfamilies there 

 would tlien be some reason for retaining these divisions, but the differ- 

 ences are so slight that they hardly enter into this consideration. 

 Thus tlie Tachiniua^ are known to attack the Hymenoptera, Lepidoptera, 

 Diptera, Coleoptera, and Ortlioptera, but not the Ilemiptera; the Phasi- 

 nai and Ocypteriua' attack the Coleoptera, Ortlioptera, and Hemiptera: 

 the Gymnosomina» attack the Hemiptera only, and thePhanime the Cole- 

 optera. It will thus be seen that all of these subfamilies, with the excep- 

 tion of the GymnosomiujTB, attack Coleoptera; that all except the 

 Tachinin;!" and Phanina? i)rey upon the Ilemiptera; while the Tacihininjp, 

 is the only one known to attack the Hymenoptera, Lepidoptera, and 

 Diptera. In point of numbers the Tachininre outnumber all of the 

 other subfamilies put together by at least fifteen species to one, and to 

 this fact alone is apparently due the greater diversity in regard 

 to their hosts. 



The most recent attempt at a classification of the Tachinida^ of the 

 world is by Brauer and Bergenstamni, of Vienna, Austria. These 

 authors, who are new workers in this field, had access to the types of 

 most of the species described byMeigen, Wiedemann, Schiner, Pondani, 

 .laennicke, and several by Macquart, and their figures and redescrip- 

 tions of many of the sjiecies can not but prove to be great aids to future 

 students of this group. In the first part of their work' they threw 

 together in one mass the five families: (Estrida^., Tachinid}©, Dexida>, 

 Sarcophagida', and Muscida', and out of this chaotic mass they erected 

 Jifty-Jive t'iumUes, which were duly given family names; but this classifi- 

 cation did not prove satisfactory to the authors, so in the third or last 

 I^art of their systematic work they again threw all the families into one 

 and divided it into sixty groups, which they call sections. 



'Published ill the, I )ciiksclui('teu «ler Mjithemiitisili-Xntiirwissenchaftlichen Classe 

 der Kaiserliclieu Akiiduiaic dcr WiHsenschui'teii lor 18S9. 



