ARTICULATA. 167 
Besides the male and female, there are some with a large head and mandibles, 
which are the soldiers, named neuters by Latreille. Pupze with the wings 
folded under the integument, are sometimes seen, and the great mass is made 
up of apterous individuals, which, from occurring of all sizes (some of them 
being very small), must be larve. They are active in all their stages, and 
the larvee present the curious fact of being the general workers of the 
colony. In the American Zermes frontalis, Hald., the pupe take their final 
form in the spring, when they take wing in the morning in great numbers. 
In a few days the wings drop off, and no winged individuals are seen. This 
species works galleries in logs and stumps of trees, and is equally abundant 
in localities suited for ants, or beneath stones, when it forms galleries in the 
ground, plastering them with a hard mixture of clay. They are never seen 
out of their burrows except in the winged state. A species in Western 
Africa, Z. fatalis (pl. 79, fig. 56c), builds conical nests ten or twelve feet 
high, with turrets rising from the surface, and having the entrances beneath 
the ground. When gravid, the female of this species (pl. 79, fig. 56 @) has 
the abdomen many thousand times its natural size, being nearly three inches 
long and three fourths of an inch in diameter, and containing about eighty 
thousand eggs, which are discharged in twenty four hours. The female, at 
the time of depositing her eggs, is walled within a hollow prison of clay 
shaped like a flat apple or turnip, the margin of which is perforated with a 
row of small holes through which the eggs are said to be ejected. A small 
species in France destroys furniture, woodwork, and records, its presence 
being seldom known until it is too late. 7! frontalis has not been known 
to appear about houses. Dr. T.S. Savage made extensive observations 
upon 7. fatalis, which are detailed in the fourth vol. of the Proceed. Acad. 
Nat. Sci. 
The little apterous louse-like insect, Zroctes pulsatorius, found among 
bocks, belongs to the family of Psocide. Perla bicaudata (pl. 79, fig. 67) 
is a representative of the Perlide. 
The Lphemeride (pl. 79, figs. 70, 71, 72) are well known by the four 
wings with nervures in both directions, the anterior pair much the largest, 
the organs of the mouth but little developed, and the abdomen ending with 
long sete. The larvee live in the water, and the adults are fond of flying 
in the air, rising vertically above a certain spot, then falling slowly with 
their wings expanded. These insects were known to Aristotle and lian, 
who named them in allusion to their short life, which in general extends 
from three hours to a day, although by keeping the sexes apart they will 
live from one to three weeks. When they leave the pupa state they fly off 
apparently perfect insects, but the succeeding night they cast off another 
thin pellicle from all parts, including the wings, and this being found at a 
distance from the water, and bearing a considerable resemblance to the 
pupa case as it stands attached by the feet to various objects, conveys the 
false impression that the pupee are able to walk a great distance before they 
are transformed. Pictet of Geneva is the chief authority upon this 
family. 
The Libellulide are composed of various genera, among which are 
371 
