Common Cockroach. 89 



possible that the aberrant arrangement observable in the Blattinae 

 may foreshadow the more usual one in which a single receptaculum 

 seminis has a gland of a secretory character superadded to it. And, 

 as the number of the ' colleterial ■" tubules is very considerable, they 

 may be taken, perhaps, to correspond not only to the colleterial 

 glands of other insects, but also to their so-called ^ scent glands/ The 

 food, and to a considerable extent the habits, of the larvae and of 

 the adult insect being identical in this family, we find little differ- 

 ence existing between their internal structural arrangements beyond 

 that which a greater prominence in the evolution of the reproductive 

 apparatus constitutes. The retention of the ' fat body^ is obviously 

 correlated with the absence of any period of quiescence and absti- 

 nence from food, such as that of the pupa stage of Metabolous 

 insects, and of the need for a supply of force which the changes 

 gone through by those classes entail. Externally the imperfect 

 insect in the class Orthoptera does not, with the exception of the 

 Orthoptera Amphibiotica, such as the Libellulidae and Ephemeridae, 

 differ from the adult by the possession of any provisional organs of 

 which the perfect insect is destitute, but contrasts with it almost 

 exclusively by inferiority of size, by the smaller number of facets in 

 its corneae, by the absence of wings, and in this family by a greater 

 lightness of colour. Great differences, however, exist as to this 

 latter particular between adult individuals of this species. 



For a monograph of the order Orthoptera, see the Latin work, 

 ' Orthoptera Europaea,^ Auctore Leop. Henrico Fischer, Lip- 

 siae, 1 853, where a general account of the external and internal 

 anatomy of the entire order will be found, pp. 5-32, and an 

 account of the anatomy of the family Blattinae will be found, 

 pp. 84-88. See also Leon Dufour, Recherches Anatomiques et 

 Physiologiques sur les Orthopteres, 1834, Mem. Acad. Sci., 

 torn, vii., des Savans Etrangers; also in 4to, Paris, 1841. At 

 pi. v., figs. 44—47, good figures of the digestive and reproductive 

 systems are given. See also PI. vi. infra, with description. 



For a monograph on the digestive and renal systems of this insect, 

 see S. Basch, Sitzungsberichte, Kaiser Akad. Wiss. Wien, 

 vol. -^^^ 1858, p. 234, Math. Nat. Classe. 



An account of the natural history, as well as of the anatomy of the 

 common Cockroach, may be found in a short monograph. 



