18G DR. A. D. IMMS ON 



remarkable, and is mostly owing to the fact that three nests (nos. 68, 89, and 125) 

 contained no fewer than 39 male individuals among them; in no other instances were 

 more than five males found in a single nest. The females have a marked tendency to be 

 solitary, which is indicated by the fact that 73 nests, or 61 per cent, of the total number 

 examined, contained single individuals only. In the cases of the males this tendency 

 does not appear to be evident. Out of 42 nests containing males, in only 9 (or 

 14 per cent.) were single specimens found. 



The form assumed by the nests is very variable (PI. 36). As a general rule, at least 

 three secondary or side tunnels are constructed, and these communicate with the larger 

 main tunnels of the nest. Certain of the side tunnels serve as entrance or exit passages, 

 while others terminate blindly. In most nests there is usually a hole or aperture present, 

 leading from one of the tunnels into the ground. This hole is the entrance to a subter- 

 ranean passage or chamber (u.c. in PI. 36) ; in some instances this chamber was found 

 to he lined with silk, while in others no silk was present. When disturbed the occupants 

 of a nest frequently take refuge in these subterranean passages, but it is by no means 

 always the case. I helieve that their primary function is that of a place of retreat 

 during the dry hot weather. The nests further vary very much in size, aud this to a 

 large extent depends upon the number of occupants therein. In the case of nests 

 inhabited by a single individual, or in some cases two individuals, only one or two 

 elongate tunnels of loosely woven silk are constructed, and the contained Etnbiids show 

 clearly from within. In those instances where several Embiids exist in association with 

 one another, they all participate in the formation of a common nest. The latter then 

 assumes the form of a somewhat comjfiex ineshwork of tunnels. In the most complex 

 nests a series of superposed tunnels is present, the lowest layer extending for a short 

 distance into the earth. Such nests are the result of the combined efforts of a large 

 number of occupants. Much more silk is expended on their construction, and the walls 

 of the tunnels are denser and whiter in appearance. A typical large nest is shown in 

 text-fig. 6. The largest number of individuals found inhabiting any single nest was 21. 

 Nest no. 47 (PI. 36. fig. 2) contained four females and one male, and measured 1 foot 

 4 inches in length. Nest no. 20 (fig. 3) contained a single female only, and was excep- 

 tionally large for the work of one individual ; it measured 11^ inches in greatest length 

 and 5t; inches in maximum width. Nest no. 26 (fig. 4) contained one male and one 

 female. Nest no. 39 (fig. 5) contained two females ; and nest no. S5 (fig. 8) contained 

 one male, one female, and one immature male. 



The first step in the construction of a nest consists in the spinning of a tolerably 

 straight silken tunnel about 3 or 4 inches in length (fig. 1), and many nests occupied 

 by single individuals remain in this simple condition. From a reference to the table 

 given on p. 188, it will be noted that nests nos. 68, 76, 89, and 125 contained 21, 10, 19, 

 and 12 occupants respectively. Such nests attain a relatively high degree of complexity 

 (vide text-tig. 6). The various individuals contribute towards the construction of these 

 large nests, and exhibit in this respect something more than a simple gregarious instinct. 

 I regard these nests as a manifestation of an incipient tendency to colony formation, 

 which has undergone little or no evolutionary development. Captive Embiids, wheu 



