232 THE entomologist's record. 



at a time. One remarkable fact established by the author, is that 

 polyandi'y exists among them and " forms an important factor in 

 accounting for variations." 



Several pages are devoted to descriptions of the ova, ecdyses, 

 phylogeny as suggested by metamorphoses, their enemies, both internal 

 and external, and to the external anatomy, which is described in some 

 detail. 



A kind of appendix, from page 167 to page 185, is occupied by a 

 series of notes on " Vivarium Experiments " ; we find a large number 

 of notes with such titles as " Habits in confinement" ; " Fifteen in a 

 hrood oi Tetti^i^ ornattis" : "Males weaker than females"; "Third 

 ecdysis of T. ornatns, growth depends on food supply " ; " T. oniatus, 

 fifteen days incubation " ; " T. urnatiis, hatching in June comes to 

 maturity in August" ; " Oviposition of T. ornatna" : " T. oruattis and 

 2\ triannidaris in conjugation . . . . "; " Expulsion of faeces by 

 means of hind tibia"; " Tettigids play in the sunshine, trying their 

 wings"; " Mutilation not inherited in the offspring . . . ."; "Deformity 

 of the tibifie in Tcttii/idae newly-born . . . . " ; and so on, 

 forming an interesting list of notes taken upon the habits of several 

 species of Tettiijidcu' kept under observation in captivity, with dates of 

 their exclusion, ecdyses, copulation, the whole series of experiments 

 forming an excellent example to British orthopterists who may well 

 make up for the poverty of the fauna which they have to study, by 

 more thoroughly examining from every point of view, the few species 

 which come in their way. 



Migration and Dispersal of Insects: Social Insects— Hymenoptera, 



Termites. 



By J. W. TITT, F.E.S. 



Hudson says {Ent. Mu. May., xxvi., p. 23) that, in New Zealand, 

 when he has observed the annual flights of Atta antaictica there, he 

 has heard the peculiar " humming in the air," described by White of 

 Selborne, very distinctly, and has little doubt that the sound which so 

 puzzled the renowned naturalist was caused by a migration of ants in 

 the higher regions of the atmosphere. This species, which is very 

 abundant on the hills round Wellington, performs its annual flight 

 with great regularity. On April 1st, 1888, enormous numbers of the 

 (J s were observed flying about over a very large extent of country. 

 . The same phenomenon was exactly repeated on May 31st, 

 1889, when the ants were, if anything, even more abundant. Both 

 days were calm and sunny, and no doubt this species takes advantage 

 of the flne weather that usually prevails about this time to perform 

 its annual migrations. Hudson considers that the " stocks " of the 

 several nests must be completely mixed up by the process, and con- 

 siders it remarkable that the males and females should escape simul- 

 taneously from the different nests over so wide an area. Another New 

 Zealand observer, W. W. Smith, writing in September, 1890, says 

 {loc. cit,, pp. 321-322) that, before the time for the swarming and 

 migration of Tetrainuriuiti nitidinn, a very minute species of ant, 

 in that year, he Avrote to several friends in different parts of 

 Canterbury requesting them to keep a strict lookout for any flights 

 of insects that might to appear in their districts, at the same 



