204 SUMMARY OF CURRENT RESEARCHES RELATING TO 



that of the biting Orthoptera and the sucking Ehynchota. With both 

 they agree in having a free prothoras ; with regard to other parts of 

 their exoskeleton they agree sometimes with one and sometimes with the 

 other group. The wing is of the pterophorine type. In the possession 

 of a concentrated nervous system the Physopoda come very near to the 

 Ehynchota, and are widely separated from the Orthoptera, the aberrant 

 Mallophaga, however, having also a concentrated nervous system. The 

 tracheal system has only three or four pairs of stigmata, but such a 

 reduction is often seen among holometabolous insects. The digestive 

 apparatus is characterized by having only four Malpighian vessels, as is 

 the case in most Ehynchota, except the Aphides which have none, and 

 the CoccidsB which have only two tubes. Most Orthoptera have a 

 number, but the Termites and the Psocidse have only six, and the 

 Mallophaga four. 



The male generative apparatus with its simple, often pyriform testi- 

 cular tubes, is somewhat like that of both the Mallophaga and the 

 Phytophthira ; the female organ, by the rosette-like arrangement of the 

 few ovarian tubes, resembles the tubes of the Ehynchota. On the whole, 

 then, the Physopoda appear to have a closer anatomical resemblance to 

 the Homoptera than to the Orthoptera, and there are certain biological 

 facts which sustain this conclusion ; and there can be no doubt that the 

 Physopoda should be separated from the Orthoptera. 



It depends upon the view which we take as to the general classifi- 

 cation of Insects as to what we shall next do ; if we hold to the old 

 views, we must place the Physopoda with the Ehynchota, and divide 

 that order into Heteroptera, Homoptera, and Physopoda. If, however, 

 we break up the " conglomerate " of Orthoptera into several orders equal 

 in value to such as the Coleoptera or Diptera, we should destroy the 

 true rhynchote type by inserting the Physopoda under it, and we must, 

 in that case, make a special order for them. Such an order would stand 

 between the Ehynchota and the Conodontia (or Mallophaga, Psocidas, 

 and Termites). It might be defined as having, among others, these 

 characters : a very small body ; a hypognathous head ; unsymmetrical, 

 sucking mouth-parts ; antennae with seven to nine joints ; facetted eyes, 

 large ; generally three ocelli. Thoracic rings pretty long ; prothorax 

 free ; metanotum longer than mesonotum ; mesophragm free, mctaphragm 

 absent ; abdomen with ten segments, anal segment often tubular. Legs 

 short ; tarsus with one or two joints. Two pairs of very small wings, 

 with nervures reduced. Three or four pairs of stigmata. Four Mal- 

 pighian vessels ; two pairs of salivary glands. Nervous system concen- 

 trated. Heart small. With or without an ovipositor, female orifice 

 between eighth and ninth or ninth and tenth abdominal segments ; male 

 orifice between ninth and tenth. Eeproduction sexual or parthenogenetic. 

 Germinal stripe completely internal. Larva like imago, nymph does not 

 feed, but larva and imago phytophagous. 



New Organ and Structure of Hypodermis in Periplaneta orientalis.* 

 — Mr. E. A. Minchin gives an account of an undescribed organ in the 

 Cockroach. Two pouch-like invaginations of the cuticle lie close on 

 each side of the middle line, between the fifth and sixth terga of the 

 abdomen. They are lined by a continuation of the chitinous cuticle, 

 which forms, within the pouches, numerous stiff, branched, finely pointed 



* Quart. Journ. Micr. Sci., xxix. (1SS8) pp. 229-31 (1 pi.). 



