1<)2 DR. A. D. IMMS ON 



The incubation period of the eggs varies between about 23 and 30 days. They are 

 parasitised by a minute Hynienopteron of the genus Embidobia, Ashm., family Scelionidae. 



The newly hatched larva is 16 mm-1'8 mm. long, and entirely white, with the excep- 

 tion of the eyes and the strongly chitinised apices of the mandibles. It is a relatively 

 specialised example of the Campodeiform type of larva, and exhibits no primitive features 

 which do not also occur in the female imago. The chief characteristics are the relatively 

 great size of the head, nine evident abdominal segments, and 9-jointed antennas. The 

 enlarged 1st joint of the anterior tarsi is present as in the imago. 



Larval growth consists chiefly in increase in size, increase in the length of the abdomen, 

 the adding of numerous joints to the antenna?, and the darkening of the coloration. 

 The larval period lasts from the end of July or the beginning of August until the 

 following May. 



The nymph stages last about two months during May, June, and July. The female 

 nymph does not differ from the adult except in colour and degree of chitinisation. The 

 male nymph is chiefly characterised by the presence of wing-pads. 



The characteristic asymmetry of the terminal abdominal segments of the adult male is 

 acquired very late in development, not being evident until the end of the nymphal period. 

 For this reason it is probably a phylogenctically recent acquisition. In the larva?, the 

 female, and the nymphs of both sexes a well-defined 10th sternum, consisting of a pair 

 of symmetrical plates, is present. The subgenital plate of the adult male is probably 

 formed by the fusion of the right 10th sternal plate with the 9th sternum, the left 10th 

 sternal plate persisting as the " ventral process." 



A study of the wing-neuration shows a remarkable degree of variation, no two speci- 

 mens being identical. Many of the variations are reversions to a generalised state 

 exhibited in more primitive genera. 



The larva?, nymphs of both sexes, and females are vegetable feeders, and the mandibles 

 of the larva? and nymphs closely resemble those of the females ; they differ from those of 

 the male in being much stouter and provided with a crushing-edge. The possibility 

 of the male alone being carnivorous requires further research. 



11. Bibliography. 



Comstock, J. H., & Needham, J. G. (1898) .—The Wings of Insects. Amer. Nat. vol. xxxii. pp. 4.23-424. 

 Endeklein, G. (1903). — Ueber die Morphologic, Gruppierung, unci systeniatische Stellung der 

 Corrodentieu. Zool. Anz. Bd. xxiv. pp. 423-37. 



(1909). — Die Klassification der Embiiden, nebst morphologischen und physiologischen Bemerk- 



ungen, besonders iiber das Spinnen derselben. Zool. Anz. Bd. xxxv. pp. 166-91, 3 figs. 



■ (1912). — Embiiden. In: — Collections Zoologiques du Baron Edna, de Se'lys-Longcharnps, 



Fasc. in. No. 5, pp. 1-121, pis. 1-4, and 76 text-figs. 

 Fkiedrichs, K. (1906). — Zur Biologie der Embiiden. Neue Untersuchungen and Uebersicht des 



Bekannten mit Beitragen iiber die Systematik und Postembryonalen Entwicklung niediterraner 



Arten. Mitt. Zool. Mus. Berlin, iii. pp. 213-40, with 19 text-figs. 



(1907). — Zur Systematik der Embiiden. Verb, zool.-bot. Ges. Wien, Bd. lvii. pp. 270-75. 



