408 LEPIDOPTERA 



CHAP. 



larva is provided with two sets of setae, one set consisting of very 

 long hairs, the other of setae radiating from warts ; each one of this 

 second set of spines has a small bladder in the middle, and it has 

 been suggested that these assist in the dissemination of the young 

 caterpillars by atmospheric means. 1 These aerostatic setae exist 

 only in the young larva. The markings of the moth are very 

 variable ; melanism is very common both in the larva and imago ; 

 it has been shown conclusively that these variations are not 

 connected, as black larvae do not give a larger proportion of black 

 moths than light-coloured caterpillars do. In England this 

 moth is never injurious. A closely allied form, Ocneria dispar, 

 was introduced by an accident into North America from Europe 

 about thirty years ago ; for twenty years after its introduction it 

 did no harm, and attracted but little attention ; it has, however, 

 now increased so much in certain districts that large sums of 

 money have been expended in attempting its extirpation. 



DasycMra pudilmnda has occasionally increased locally to an 

 enormous extent, but in the limited forests of Alsace the evil was 

 cured by the fact that the caterpillars, having eaten up all the 

 foliage, then died of starvation. 2 Team melanosticta is said to 

 produce columns of processionary caterpillars in Australia. 



Fam. 33. Hypsidae (or Aganaidae). -A family of compara- 

 tively small extent, confined to the tropical and sub-tropical 

 regions of the Eastern hemisphere. The colours are frequently 

 huff and grey, with white streaks on the outer parts of the wings. 

 We have nothing very like them in the European fauna, our 

 species of Spilosoma are perhaps the nearest approach. In 

 Euplocia the male has a pouch that can be unfolded in front of 

 the costa at the base of the anterior wing; it is filled with very 

 long, peculiar, hair-like scales growing from the costal margin ;. 

 both sexes have on each side of the second abdominal segment 

 a small, projecting structure that may be a sense-organ. The 

 female is more gaily coloured than the male. 



Fam. 34. Arctiidae. With the addition recently made to 

 it of the formerly separate family Lithosiidae, Arctiidae has 

 become the most extensive family of the old liombycid series of 

 moths, comprising something like 500 genera and ,'5000 species. 

 Hampson recognises four sub-families Arctiinae, Lithosiinae, 



1 WacLtl and Kornauth, Mitt, for si. Fer.s //<// .sv/v.sc/t Osterreichs, Heft xvi. 1893. 

 '-' Crahay, Ann. Hoc. cut. L'clyiijttc, xxxvii. 1893, p. 282. 



