436 



C. H. TURNER 



work hard. The parasite Stelis must break through walls as 

 hard as concrete to deposit its eggs. 



Waterson (94) discusses the bird-lice of five species of English 

 auks. In addition to a parasite peculiar to it, each often has 

 one or more other parasites. He has epitomized his conclusions 

 in the following table. 



D. acutipectus, Kell 



D. calvus, Kell 



D. celedoxus, N 



D. megacephalus, D . . . . 



D. merguli, D 



D. iderodes, N 



D. cardiceps, P 



o 



11 birds 



Ud) (S) 



'a 



HO 



6 birds 



fx(6) 

 U(l) (S) 



x(DO) 



e 



6 birds 



x(6) 



CO 



SI, 



a. 



so 





11 birds 



CO 



3 

 3 



so 



10 birds 



x(H) 



fx(10) 



1 



U(i)(S) 



e 



e 



CO 

 CO 



1 bird 



x 



CD CO 



(S) 



a 



CD 



^2 



'— a 

 a 



GO £ 



CO 



CD .. 



a-s 



An x denotes the occurrence of Docophorus on bird species. The number in 

 brackets indicates how often the parasite has occurred on the host species. 



The long brackets with their numbers show how often and how many species 

 have occurred together on an individual host. 



(S) = straggler. 



Thus, column one reads: "Of Uria troile, 11 birds have been examined and on 

 all D. calvus has been taken. In two cases D. calvus has been found with D. cele- 

 doxus, and once with D. merguli. This last, however, seems a case of straggling. 



SOUND PRODUCING ACTIVITIES 



Regen (72) mentions the enticement of the female of a cricket 

 (Gryllus campcstris) by the stridulations of the male. 



Mrs. Comstock.(17) discusses, in a popular vein, the stridu- 

 lations of crickets and gives directions for keeping the insects 

 in confinement. 



Aubin (2) has performed some experiments which cause him 

 to assert that the high-pitched note produced by flies is due 



