DESCRIPTIONS OF GENERA AND SPECIES. 233 



suspect at once that they were the two sexes of one 

 species ; but in G. dispar the male is utterly unlike the 

 female, and utterly unlike every other male in the 

 genus. Yet the female of G. dispar differs but little 

 from that of G. platygaster, a species in which the male 

 does not differ from the female more than is usual in 

 the genus, probably rather less. 



The Rostrum is small ; not usually distinctly divided 

 from the remainder of the cephalo thorax. It is some- 

 times truncated anteriorly to allow the mandibles to 

 protrude, as in G. plumiger, G. palmifer, etc. Some- 

 times it forms a more or less chitinous hood over them, 

 as in G. platygaster, G. dispar, etc. 



The Mandibles are chelate, usually short and power- 

 ful ; generally either tri- or quadri-dentate on each arm 

 of the chela. 



The Maxillary Lip is of the typical character in the 

 family membranous, broad in the proximal part, and 

 inclined to separate into maxillae and central lip at the 

 distal end ; but the maxillae are not functional. 



The Palpi are of three joints ; the basal joint may 

 be anchylosed to the maxillary lip. 



The Cephalothorax is small, and greatly hidden by the 

 anterior portion of the abdomen in such species as G. 

 dispar, G. platygaster, etc. ; much larger and not at all 

 hidden in such as G. plumiger and G. palmifer. 



The Notogaster is strongly arched in such species as 

 G. spinipes, G. domesticus, etc., but has a tendency to 

 be flat in species like G. platygaster, G. dispar, etc. It 

 is usually provided with abundant hairs or their homo- 

 logues ; these may be very long flexible hairs which 

 may be clothed with small secondary hairs, as in G. 

 spinipes, G. domesticus, etc., or may be strongly bipec- 

 tinate, as in G. plumiger, or biplumose, as in G. Canes- 

 trinii ; or the hairs may be transformed into elaborate 

 phyllomorphic stalked scales, with a central, branched 

 rachis, sometimes bearing spinelets, and a thin trans- 

 parent membrane stretched between the branches 

 and the central stem, as in G. palmifer and the foreign 



