B. C. EXTOMOLOGICAL SOCIETY. 



A DESCRIPTION OF THE EGG AND OVIPOSITOR OF CUTERE- 

 BRA FONTINELLA, CLARK. (Cottontail Bot.) 



B}^ Seymour Hadwen, D.V.. Sci.. Veterinary Researcli Laboratory, 

 Ag-assiz, B. C. 



In tlie study of the Oe.'itridae, tlie most important prul^lem at the 

 present time is to discover the \-arious methods of oviposition for the 

 different species. From an economic point of \'iew the most important 

 question is : How do the larvae gain entrance to their respective hosts, 

 after emerging from the egg? The following observations on the eggs 

 and ovipositor of Cuterebra fontinella may be of some interest. Up to 

 the present I have seen no descriptions of the eggs of any of the Cutere- 

 brae. 



The specimen from which the eggs were obtained was captured out 

 of doors on July 30th, 1914, at Agassiz, B. C. 



The measurements of the egg are: Length, 1.05 mm.; width, .03 

 mm. at the widest part. In shape it bears a resemblance to the egg of 

 Gastrophilus equi, being somewhat canoe-shaped (Plate 1, Fig. 1). It 

 possesses a deep groove on the under side, which is at least one-third 

 longer in proportion than that of G. equi. In G. equi the groove is about 

 half the length of the egg. (Plate 1. Fig. 2). On the upper side, at the 

 end, is a well-marked operculum, very similar in shape and size to that 

 of G. equi, though in the latter the operculum has reticulations differing 

 from the markings on the rest of the egg. The egg case is rough and has 

 a shagrenated appearance, the operculum not differing from the rest of 

 the egg surface. (Plate 2, Fig. 3). The groove clearly indicates that the 

 egg is meant to be attached to a hair, and that possibly the larva has. up 

 to a certain point, a similar life history to that of G. equi. If so, for the 

 emergence of the larva, moisture and friction must be supplied, such as 

 would be furnished by the tongue of the host animal when licking itself. 



The subsequent life history of Cuterebrine larvae must differ consid- 

 erably from that of G. equi; because, in the various host animals, the 

 larvae show a selective facult}" for different parts of the body. For in- 

 stance, C. emasculator selects the scrotum of Tamias striatus lysteri for 

 its final habitat. Another undetermined species, specimens of which I 

 have received, is reported to have been found in the backs of field mice. 

 Two mature larvae, which were recently sent to me from Manitoba, 

 were taken from the costal region of a domestic cat. Possibly in this 

 case the cat was not the natural host, and the larvae acted in a similar 

 manner to those of Hypoderma bovis, when they are found in an un- 

 usual host, .\ccordina: to Railliet thev wander about and do not settle 



