Geophilomorpha

Secondary sexual characters

In most geophilomorphs the number of pairs of legs, which is always odd, varies and where this is so, the females tend to have a greater number of pairs of legs than the males, for example, in British Schendyla nemorensis there are 37–41 pairs of legs in males and 39–43 pairs in females. In the larger species Haplophilus subterraneus, there are 77–81 pairs of legs in males and 79–83 in females (Eason, 1964). In many species of the family Mecistocephalidae, however, the number of legs does not vary and is the same in both sexes, for example, 49 pairs in Mecistocephalus insularis (H. Lucas) from Africa and India and 51 pairs in M. evansi Brölemann from Iran. Analysis of broods of Henia illyrica (Meinert), Pachymerium fernigineum, Strigamia acuminata and S. crassipes has shown that female larvae have the same number of legs as the mother, male larvae two pairs less (Prunescu & Capuşe, 1972).

In many geophilids, for example species of Chaetechelyne, Strigamia and Geophilus the last pair of walking legs in males (Fig. 14) is tumescent and much more setose than that of the female which more closely resembles the normal walking legs. In some schendylids, for example Hydroschendyla submarina the last pair of legs are swollen and densely setose in both sexes. The setae are presumably sensory and the enlarged legs presumably contain glands but these have yet to be described.