388 Professor E. B. Poulton on 



Proportion of the Sexes. — In the recorded Asilid^ it was 

 found (p. 359) that females with prey were between three 

 and four times as numerous as males with prey. In the 

 Empidm tabulated above, such females are almost exactly 

 half as numerous as males carrying prey. In spite of this 

 great preponderance of the latter sex, females alone were 

 found in 7 species, males alone in only 5, while 4 included 

 both sexes. The large proportion of males is entirely due 

 to their numbers in only 4 species out of the 15, viz. 

 Hyhos grossipes, Empiis tessdlata, Empis livida, and 

 Fachymeria femorata. 



Female Empid£B loith prey captured in coitu. — This fact is 

 recorded frequently in Fachymeria femorcda* twice in 

 Empis tesscllata, Nos. 243, 244, once in E. livida, No. 273, 

 and once in E. opaca, No. 274. These instances out of 65 

 recorded cases form a much higher proportion than in the 

 Asilidm; but there are as yet no examples of the female 

 attacking the male of its own species or of a remarkably 

 cautious pursuit by the male during courtship, to support 

 the interpretation which seems inevitable in the former 

 group (see p. 367).i' 



The choice of Frcy hy Empid/v. — Only provisional con- 

 clusions can be reached in all the tabulated species except 

 E. tesscllata, with 20 records, and E. livida with 16. All 

 others, except Hyhos grossipes (7) and Fachymeria femorata 

 (6), are hopelessly insufficient. 



Hyhotinm. — The 10 records divided between three 

 pairs, show an attack upon minute Homoptera, ants and 

 Braconidm; and the MycetophilidsR and Bihionids& among 

 the Diptera. 



Empinm. — It is evident that Diptera form by far the 

 most important insect food of this sub-family. In fact, 

 we find no other prey, except in the case of Ehamphomyia 



* Vide footnote on p. 384. 



t Kirby and Spence were well acquainted with the facts recorded 

 in the above paragraph, and make amusing suggestions as to their 

 significance. Thus we read (5th edition, 1828, vol. i, pp. 274, 

 275) : — " Many species also of Empis, whose haustellum resembles 

 the beak of a bird, carry off in it Tipularise and other small Diptera ; 

 and what is remarkable, you can seldom take these insects in coitu, 

 but the female has a gnat, some fly, or sometimes beetle in her mouth. 

 Can this be to deposit her eggs in, as soon as they are impregnated 

 by the male ? or is it designed for the nuptial feast 1 " No Coleo- 

 pterous victim of an Empid is recorded in the present Memoir. On 

 the other hand, the predominance of Dipterous prey is abundantly 

 confirmed. 



