i895. SOME RECENT INSECT LITERATURE. 183 



iVIiiller, of some Brazilian larvae of the family, which breathe by 

 spiracles at the hinder end, and also by means of pupillae in connec- 

 tion with the tracheal tubes. These, protruded in water, function as 

 gills ; in air they are retracted. 



Dr. H. J. Hansen has lately given us an excellent description 

 with figures (8) of a very interesting and obscure African insect. 

 This is Hemimeriis talpoides, a small, brown, blind, wingless, cock- 

 roach-like creature, described by the late Mr. F. Walker from speci- 

 mens from Sierra Leone. On account, apparently, of its short, stout 

 legs this naturalist placed it near the Mole-Crickets, a family with 

 which it has no near affinity. Later, Mr. H. de Saumere examined a 

 single dried female, and believed he discovered therein a fourth pair of 

 jaws fused to form a second labium. On the strength of this observa- 

 tion (now shown by Dr. Hansen to have been quite incorrect) Hemimerus 

 was afterwards distinguished by being placed in an order all by itself. 

 But though Dr. Hansen has proved the jaws of the insect to com- 

 prise the three pairs always characteristic of the class, and satis- 

 factorily settled that it is an undoubted orthopteron, he has been 

 able to note some important facts in its habits and life-history. The 

 specimens which he examined came from the Cameroons, and were 

 found by their captor, in quantity, jumping about on the skin of a 

 rodent {Cricetomys) and penetrating between its hairs. Dr. Hansen 

 remarks that the jaws of Hemimerus are not adapted for sucking blood, 

 and suggests that it probably does not live parasitically on the rodent 

 itself, but preys upon smaller insects which are truly parasitic. If 

 this be so, the Cricetomys has cause for gratitude. 



The most remarkable observation made by Dr. Hansen on 

 Hemimerus is that the female bears living young in a very advanced 

 stage of development. Several embryos were found in a mother, 

 each less in size than that anterior to it in position. Between the 

 head and the pronotum, in the larger embryos, an unpaired organ 

 was noticed which Dr. Hansen believes to be " in connection with 

 the internal wall of female genital organs, and thus serve the nutrition 

 of the young ones, which are growing to the astonishing size within 

 the mother." That is to say, its function is supposed to be analogous 

 to that of the umbilical cord of a mammal. From the arrangement 

 and comparative development of the embryos. Dr. Hansen concludes 

 that only one is born at a time, an interval of several days elapsino- 

 before the next is ready to be brought forth. Such a method ot 

 reproduction is unique among insects, though, of course, examples of 

 the birth of many living larvae at the same time are sufficiently 

 familiar. 



Though the general aspect of Hemimerus reminds one of a cock- 

 roach. Dr. Hansen gives reasons for believing its affinities to be more 

 with the Forficulidffi than with the Blattidae. He would, therefore, 

 place the insect in a special family not far from that of the Earwigs. 



