ARTICULATA. 167 



Besides the male and female, there are some with a large head and mandiljles, 

 which are the soldiers, named neuters by Latreille, Pupas 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 larvjE. They are active in all their stages, and 

 the larvae present the curious fact of being the general workers of the 

 colony. In the American Ter mes frontalis^ Ilald., the pupa3 take their final 

 form in the spring, when they take wing in the morning in great numbers. 

 In a few daj's 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, T.fataUs {pi. 79, ßg. 56 c), 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 {pi. 79, ßg. 56 f?) 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. T. frontalis has not been known 

 to appear about houses. Dr. T. S. Savage made extensive observations 

 upon T.fataUs., which are detailed in the fourth vol. of the Proceed. Acad. 

 Nat. Sei. 



The little apterous louse-like insect, Trocfes imlsatorius., found among 

 books, belongs to the fiimily of Psocidce. Perla Ucaudata {pi. 79., fig. 67) 

 is a representative of the PerlidcB. 



The Epheineridoi {pi. 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 setae. The larvoB 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 exj)anded. These insects were known to Aristotle and ^lian, 

 w^ho 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 pupae are alile to walk a great distance before they 

 are transformed. Pictet of Geneva is the chief authority upon this 

 family. 



The LibelluUdce are composed r>f various genera, among which are 



371 



