presented a feature that seems to be new and noteworthy. The 
general shape of the egg (pl. XIX, fig. 2), with its grooved 
flange (a) for attachment to a hair of the host-animal, closely 
resembles that of the /Zyfoderma egg ; it is, however, somewhat 
more quadrate at the base. But at the apex of the egg, a very 
distinct, delicate reticulated area (pl. XIX, fig. 25) can be 
detected; and this readily splits away from the rest of the egg- 
envelope, so that little doubt can be entertained that it is of the 
nature of a lid, which opens to allow the escape of the newly- 
hatched larva. A comparison with the well-known life-history 
of Gastrophilus, whose egg is provided with a very distinct, cap-like 
lid, suggests that in the case of Œdemagena also the young maggot 
in licked into the host's mouth, and makes 1ts way — like the larva 
of Hypoderma — through the gullet-wall and then through the 
tissues to the final position beneath the skin of the back. It is 
remarkable that the egg of /Zyfoderma has no such delicate, 
reticulated area at the apex ; here the whole envelope is firm and 
relatively thick (pl. XIX, fig. 3). Perhaps this may be held to 
support the view lately expressed by JosT (1), that in the life- 
history of /7yfoderma not the young maggot, but the egg is 
swallowed by the host-animal, and that the larva is hatched only 
in the host's food-canal. Future researches may perhaps show if 
such a difference in habit between the two nearly-allied genera 
(Edemagena and Æ/ypoderma really accompanies the slight but 
suggestive difference in the egg-envelope described in this com- 
munication. 
(1) Zeitschr. für wissensch. Zoologie, vol. XXXVI, 1907, pp. 644-715. 

