136 



idae, Stegius and Eriximachus in the Reduviidae, described 

 by Distant, and Acanthicus of Laporte in the Membracidae. 



Hemiptera usually deposit their ova on the surface of leaves 

 or twigs, or insert them in slits made in these. The nymphs 

 are usually free, but in some groups are concealed in spume or 

 in calcareous cases, while a few form galls. They differ from 

 their adults principally by the condition of the flight organs, 

 which are gradually developed outside the body, forming in the 

 ultimate nymphal instar four, more or less free, pads. Other 

 distinctions lie in the number and form of the segments of tha 

 antennae, labium and legs, the absence of ocelli, the shape of 

 the head and nota, and the development of the genitalia. 



In the early instars, the abdomen is '^nly feebly chitinized 

 and, in some families at least, there are median and lateral 

 sternites, with very wide sublateral submembranous parts, the 

 sclerites down the middle also being widely separated one from 

 another. As the instars progress, the membranous areas 

 decrease, till they constitute merely linear separations between 

 the segments, in the fifth instar. 



In most Hemiptera, there are apparently 5 nymphal instars. 

 It is still often stated as 4 larval and one pupal, but these are 

 terms that have no place rightly in the horismology of the 

 Homomorpha. 



In the Homoptera, adult or nymphs, there are no odoriferous 

 glands though in certain Sternorhynchi there are "honey- 

 glands." In most adult Heteroptera, the orifices of the noto- 

 rious odoriferous gland are situated on the metapleura, though 

 in some there is a single opening on the metasternum medianly 

 and in a few the glands appear to be absent. 



In the nymphs of the first series, the openings are placed on 

 the (abdominal) tergites and afford valuable classificational 

 characters, which have been partially worked out (^) but 

 require much extension. 



According- to Giilde's researches, it may be supposed that the 

 Cimicidae, Aradidae, Nabidae, Reduviidae, Anthocoridae and 

 Clinocoridae possess 3 glands, opening on the fourth, fifth and 

 sixth tergites (^) ; of these, the first is paired, having two 

 openings, in many of the Cimicidae. In Lygaeidae, ]N"eididae, 



C4) In a valuable paper by Guide, entitled "Die Dorsaldriisen der 

 Larven der Hemiptera-Heteroptera", 1902 Ber. Senckenb. Naturf. Ges. 

 Frankf. a M. 85-136, Plates 7-8. 



(5) This applies apparently only to the 5th instar. 



