24 Transactions of the Society-. 



III. — Development of an Erribiid* 

 By J. C. Kershaw, F.Z.S. 



{Read November 19th, 1913.) 



Plates III, IV, and Pig. 4. 



These insects feed chiefly on the inner but dead part of the bark 

 of the trees where they live and spin their webs, but they some- 

 times eat remains of insects and other dead animal matter. The 

 male, except when breeding, seems to live under a separate web, 

 and the proportion of males to females is only about one to fifty. 

 The males fly fairly well, chiefly at night it would appear, since 

 I have had two or three come to light. 



The egg -batch is laid on the surface of the bark, or beneath a 

 loose piece or crevice thereof. When the webs and tunnels are 

 near the ground they are usually carried down between the bark 

 and the earth and grass, and the eggs are often laid on the bark 



* This Embiid is E. uhrichi de Saussure. See Note sur la Tribu des Embiens, 

 par Hemi de Saussure, Bull. Soc. Ent. Suisse, ix. (1896) p. 8. It is a very common 

 insect in Trinidad, B.W.I. 



EXPLANATION OP PLATES III and IV. 



Fig. 1. — Longitudinal section through primitive band, and front view thereof. 

 ,, 2. — Longitudinal section ; band sinking into yolk, and amnion and serosa 



growing over it ; front view thereof ; beneath, a transverse section. 

 ,, 3. — Longitudinal section through egg (embryo itself not in section), ap- 

 pendages budded ; below, a transverse section. 

 ,, 4. — The same, tail just recurved ; to the right, anterior end of embryo un- 

 rolled, showing bi-lobed labrum ; below, a transverse section. 

 ,, 5. — The same, more advanced (embryo in section) ; to right, view of a 

 maxilla ; below, a transverse section. Section i-j is through an 

 embryo of still later date, when the ventral part of the amnion has 

 disintegrated, and it is growing around the yolk laterally and dorsally. 

 ,, 6. — Longitudinal section, embryo revolved ; below, a transverse section. 

 ,, 7. — Embryo in egg ; only egg-shell (chorion) and embryonic membranes in 

 section ; below, transverse section showing appendages embedded in 

 the disintegrated material. 

 ,, 7a. — Longitudinal section of anterior part of embryo at a later date, show- 

 ing absorption of serosa and amnion. 

 N.B. — In all but fig. 7 the chorion, or egg-shell, is not shown. 

 Lettering of Figures: — am, amnion : at, antenna; cli, chorion; cu, cuticle; ec, 

 ectoderm; I, leg; Ibr, labrum ; m, mandible; mi, mid-intestine; mx 1 , first 

 maxilla ; mx'-, second maxilla ; o, oolemma ; pel, procephalic lobe ; pr, proc- 

 todeum ; rs, remains of serosa ; s, serosa ; ss, membrane secreted by serosa ; 

 st, stomodffiurn ; y, yolk ; ys + as, substance formed by remains of part of the 

 yolk and amnion ; la, 10a, and 11a, first, tenth, and eleventh abdominal 

 segments. 



