ELEGANT COCKROACHES 



233 



is from its male. In Blattidae it is always the case so far as 

 is yet known that when there is a difference as regards the 

 alar organs between the two sexes, it is the male that has these 

 structures most developed, and this even when they can be of 

 little or no use for purposes of flight. 



Among the most interesting forms of the family are the two 

 species of the genus Nocticola, recently discovered by M. Simon 

 in caves in the Philippine Islands. 1 They are amongst the 

 smallest of the Orthoptera, the male being scarcely -| of an 

 inch long. In the larval state of A 7 ! simoni the ocular organs 

 exist as three ocelli, or facets, on each side of the head, and in 

 the perfect state the number is increased somewhat, as shown in 

 Fig. 127, A,. In the second species of the genus the female is 

 quite blind (the male being still undiscovered). The fenestrse 

 in Nocticola are absent ; the tegmina and wings are totally 

 wanting in the female (Fig. 127, B), but are present in a very 

 peculiar condition in the male (Fig. 127, A x ). There are other 

 anomalies in the structure of these cavernicolous Insects, the 

 cerci being apparently of peculiar structure, and the spines of 

 the legs more hair-like than usual. ^-aca>^ 



The condition of the eyes is remark- 

 able ; the peculiarity in their de- 

 velopment is worthy of study. 



To those who are acquainted 

 with Blattidae only through our 

 domestic " black beetle " it may seem 

 absurd to talk of elegance in con- 

 nexion with cockroaches. Yet there 

 are numerous forms in which grace 

 and beauty are attained, and some 

 exhibit peculiarities of ornamenta- 

 tion that are worthy of attention. 

 Cory dia, petiveriana (Fig. 128) is a 

 common cockroach in East India. It 

 has an effective system of coloration, Fl - 128 - Omydia .petiveriana, with 



tegmina extended, A ; closed, B. 



the under wings and the sides of 



the body being vividly coloured with orange yellow ; when the 

 tegmina are closed the upper surface of the body is of a velvet- 

 black colour, with cream-coloured marks ; these spots are different 

 1 See Bolivar, Ann. Soc. ent. France, 1892, p. 29. 



