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Show 1897.] OF THE LEGS IN THE BLATTIDiE. 905 Brunner1 quotes Serville's remarks, and states that he could add a large number of cases. H e observes that the abnormal tarsus is usually unilateral and on the posterior legs (Nyctihora, Epllampra, & c ) . The above-mentioned authors examined only small numbers of individuals, and it was therefore desirable to extend the inquiry as to the frequency of occurrence of abnormal tarsi through greater numbers. This has been done among certain easily obtained species, the total numbers examined being:- TABLE A. Periplaneta americana Phullodromia aermanica Sty/opyga orientalis Adult. 750 230 102 1635 Young. 180 411 0 1976 Total. 930 641 102 3611 The specimens of P. americana and P. germanlca were obtained from the Society's Gardens, those of P. uustralaslce from the Botanic Garden, Cambridge (where the egg-cases of this species appear to have been introduced in packets of plants from K e w and South America), and those of S. orientalis from Cambridge bakehouses, except 262 captured in a bakehouse at Poole, Dorset. The specimens of P. americana and P. germanlcu were caught by hand, and those of the other two species by traps. This probably explains the small number obtained of the young of the two former species, as the larger adults are more easily picked up. It is possible that some of the young of P. germanlca were wrongly included as belonging to P. americana, for both species occur in the same warm houses in the Society's Gardens. A n examination of these specimens showed the percentage frequency of occurrence of individuals with one or more tarsi four-jointed to be as follows :- TABLE B. Adult males. 21*8 169 14*9 20-6 Adult. females. 28-5 232 164 21-8 Total adults. 25*2 200 15-7 21-4 Young. 8*3 14-8 164 Total. 21*9 16-7 15*7 18*7 1 Nouv. Syst. des Blattaires, p. 146. PROC ZOOL. Soc--1897, No. LX. 60 |
