THE EGG-CARRYING HABIT OF ZAITHA. 
FLORENCE WELLS SLATER. 
Ir is a well-known fact that certain bugs of the family 
Belostomidz carry their eggs on their back until they are 
hatched. This has been frequently observed in the case of 
Zaitha fluminea, which is common in the Atlantic States, and 
with Serphus dilatatus of the Western States. 
It has been taken for granted by all who have described this 
habit that it is the female that carries the eggs. And Dim- 
mock even states!: “These eggs are set nicely upon one end, 
and placed in transverse rows, by means of a long protrusile 
tube, or ovipositor, which the insect can extend far over her 
own back.” Investigation proves, however, that, in the case of 
Zaitha at least, the credit of carrying the eggs belongs to the 
male, and that the ovipositor of the female is so short as to 
make it impossible for her to reach her back with it. 
In the course of a study of the reproductive organs and 
genital armature of Zaitha, made in the entomological labora- 
tory of Cornell University, I have had occasion to dissect many 
egg-bearing individuals, and in every case they have proven to 
be male. 
The specimens used were collected in the vicinity of Ithaca, 
where the species is abundant in ponds; and as the egg-laying 
season lasts from June until the latter part of August, it was 
easy to obtain material for study. The insects were found 
most abundantly in shallow water, quite near the shore, cling- 
ing to the underside of aquatic plants, especially Marsilia. 
The eggs of Zaitha are very large as compared with those of 
other insects. They number from seventy-five to eighty-five 
and are placed in regular diagonal rows on the upper side of 
the wings of the male. This makes a heavy load for the male 
1 Annual Report of the Fish and Game Commissioners of Massachusetts (1886), 
ot. 
93! 
