68 Habits of the Tomato Moth 



(i) The Moth. 



The moth measures \\ to If inches (35-40 mm.) across the wings. 

 The fore wings are purplish brown, sometimes brownish drab, with a 

 few scattered white scales. The first and second lines across the wings 

 are very faint and there is a fine well-marked white subterminal line 

 provided with two sharp median tooth-like projections. The orbicular 

 and reniform stigmata are usually whitish edged, the former bearing a 

 yellowish spot in its centre. Hind wings greyish, usually with a fuscous 

 discal crescent and a posterior clouding or suffusion. There are no 

 sexual differences in the markings. The general appearance of the insect 

 may be gathered by a reference to South's Moths of the British Isles, 

 Vol. i, PL 120. 



The females largely outnumber the males. From among 152 moths 

 bred from pupae in the laboratory, 103 (68 per cent.) were females and 

 49 (32 per cent.) were males: out of 1230 trapped in the greenhouses 872 

 (71 per cent.) were female and 358 (29 per cent.) male. The sexes were 

 distinguished by squeezing out the genitalia after death. The proportion 

 of females is therefore about 70 percent., and as in cages where the moths 

 were kept in their natural proportions practically all the eggs were fertile, 

 it must be assumed that one male can fertilise several females. 



The moths in the greenhouses hide under clods of earth or amongst 

 the mulch, sometimes in dark places under the gutter-boards and occa- 

 sionally on the undersides of the leaves. They are rarely seen by day 

 except when they are disturbed by watering. They commence to fly at 

 dusk and may then be seen beating along the glass and endeavouring 

 to escape. Sometimes they work along cracks where fresh air flows into 

 the houses and attempt to force their way through. This attempted 

 and partially successful emigration of the moths is probably due to a 

 dislike for the atmosphere of the houses, as other species which pass in 

 by accident behave in the same way. These activities draw a large 

 proportion of them to that part of a block of glasshouses which is most 

 strongly lit at dusk, and thus an end house of a block, or the ends of 

 all the houses along one side, become more heavily infested with cater- 

 pillars than the other parts. These heavily infested parts, in the cases 

 which have been investigated, have always been found to be towards 

 the south-west. Additional evidence of this is afforded by the following 

 facts. In systematic trapping by means of 36 traps, evenly distributed 

 through a block of 12 houses over a long period, 1444 moths were caught 

 in the 12 traps along the southern side upon which the light at sunset 



