23 
Eggs of Culicidae. 
out Ross’s statement, but I clo not think the normal habit can 
be to deposit the ova on land, although it may be done in dry 
weather under compulsion ; but as a rule gravid females will 
retain their eggs until a suitable place to deposit them is found. 
On the other hand, in the Report of the Malarial Expedition 
of the Liverpool School of Tropical Medicine (p. 19), it is said 
that, “ The eggs appear to be laid singly on water, but cohere 
by their ends, forming typical- triangular patterns, and also 
adhere to floating objects, the sides of the vessel, &c. We 
observed no facts indicating that they are ever laid on solid 
surfaces.” There is little doubt but that they are only laid on 
the surface of the water. They will not retain their vitality for 
long if kept in dry earth. 
Professor Howard, who has lately worked out the life-history 
of Anopheles maculipennis so completely, gives the following 
description of the ova: “ The eggs are not attached together 
except that they naturally float close to each other, and there are 
from 40 to 100 eggs in each lot. The egg of Anopheles (Fig. 20) 
when seen from above is of a rather regular elliptical outline, 
the two ends having practically the same shape ; seen from the 
side it is strongly convex below and nearly plane above; seen 
from below it is dark in colour, and when examined with a 
high power is seen to be covered with a reticulate hexagonal 
sculpturing. At the sides, in the middle, there appears a 
clasping membrane with many strong transverse wrinkles. Seen 
from above, the egg is black except for the clasping membrane 
which nearly meets in the middle line in the middle third of the 
body, but retires to the extreme sides for the anterior and 
posterior thirds. At each end the colour is lighter with a group 
of from five to seven minute dark circular spots. It is 
0 • 57 mm. long.” 
Grassi also figures the ova of A. claviger (i.e. haculipennis) 
and those of A. bifurcatui , an interesting difference being that 
those of the latter are arranged in star-shaped groups, whilst 
those of the former are in more or less irregular lines (Fig. 20, III.). 
Nuttall and Shipley give the measurement of the ova of 
Anopheles maculipennis as 0 * 7 to 1 • 0 mm. in length hnd 0*16 mm. 
at the greatest breadth, somewhat larger than that given by 
Howard (0*57 mm.). These observers state that when fresh 
laid they are white, but soon darken in colour to a grayish- 
black, and that “ if the eggs are subject to much attrition, 
a delicate membrane splits off, which gives the surface of the 
