Hudson. — N .Z. Insects illustrating Principle of Sexual Selection. 437 



breed a female tliey can, by enclosing the same in a gauze-covered box 

 and placing it at an open window, attract quite a large number of males. 

 Experiments have been made to ascertain the means by which the males 

 are enabled to find the female when situated at such remote distances, and 

 the mode of tracking by scent does not afiord a satisfactory explanation. 

 In fact, there appears to be little doubt that the mysterious faculty is 

 located in the heavily branched antennae, and that some sort of communi- 

 cation is set up of the nature of wireless telegraphy. 



6. Order Hymenoptera. 



In this important order, which includes the ants, bees, wasps, ichneumon 

 flies, and their allien, the principal differences between the sexes relate to 

 special structures, such as the pollen-bearing apparatus of the hive-bee, 

 useful to the female in tending the young. They do not, therefore, concern 

 us in connection with the subject of this paper. A few of the Hymenoptera 

 are brilliantly coloured in both sexes, and in those instances where warning 

 colours are not indicated this may be due to the efiects of sexual selection. 



7. Order Coleoptera. 



The order Coleoptera, comprising the beetles, is the highest order of 

 insects, and also contains the greatest number of species, of which about 

 150,000 are known to science. Commencing with that division known as 

 the Lamellicorns, on account of the structure of their antennae, we find 

 that a striking disparity between the sexes exists in our native stag-beetles. 

 The males of the genus Lissotes have a large head and jaws and a very large 

 prothorax, these salient features being strikingly absent in the females. 

 Amongst allied genera in the tropics the most bizarre forms exist, many 

 of the males having huge horny processes on the crown of the head and on 

 the back of the prothorax ; and unless these extraordinary structures are 

 useful in making ah impression on the female sex it seems impossible to 

 assign any reason for their presence in the male sex alone. 



The male of our interesting, though dull-coloured beetle, Rhipistena 

 luguhris, has the joints of the antennae furnished with long lateral processes, 

 the whole organ forming a conspicuous fan. This remarkable structure is 

 also present in the female, but in a very reduced form. In the male of our 

 most beautiful Longicorn beetle, Coptomma variegata, the antennae are 

 nearly twice as long as in the female, and in a variable degree this disparity 

 prevails amongst the numerous Longicorns we have in New Zealand. The 

 male in the curious genus Exilis, a genus belonging to the Anthribidae, 

 a family of weevils, also possesses enormously long antennae, those of 

 the female being often less than half the length. The male of Psepholax 

 coronatus, a short stumpy -looking weevil, has a conspicuous coronet pf spines 

 on the back of each of its elytra. This structure is entirely absent in the 

 female and in all the other members of that extensive genus of weevils. 

 Very striking sexual differences are also present in Paranomocerus sjnculus, 

 the male of this fine weevil being fully twice the size of the female, and 

 furnished with a long rostrum and very long elbowed antennae. 



All the sexual disparities amongst our native beetles are, however, 

 completely overshadowed by those present in the huge Brenthid Lasio- 

 rhjnchus harbicornis, undoubtedly one of the most striking and interesting 

 insects we have in New Zealand. The male, which is usually about twice 

 the length of the female, has an enormous rostrum, with the antennae 



