PRELIMINARY LIST OF THE LEPIDOPTERA OF MALTA. 275 



guard against this wind that it is found necessary to enclose the 

 fields with walls. 



From February to May is the period during which the ento- 

 mologist in Malta will find most occupation. At this time the 

 ground is carpeted with greenery ; the fields are full of the early 

 crops of beans and cereals and the dark scarlet-flowered "suUa," 

 and are brilliant with poppies, buttercups, narcissi, asphodel, and 

 other wild flowers ; even the rocky sides of the wieds are gay 

 with clumps of the Mediterranean heath sprouting from cracks 

 and crannies in the bare rock. 



After about the end of May the vegetation begins to get 

 withered up, and in some places dies away altogether, leaving a 

 bare, dust}^ glaring surface of rock which looks, as if it never 

 had supported, nor ever again could bring forth, even the most 

 hardy of weeds. But with the first rains, at about the end of 

 September, vegetation makes a sudden reappearance, and pre- 

 viousl}'' dusty wastes soon become green with grass, and especi- 

 ally with a species of Oxalis, which springs up everywhere with 

 marvellous rapidity, and which has a remarkably lush and 

 verdant appearance. 



With regard to this drying-up of the herbage in the summer 

 months, it seems at present a mystery what becomes of some of 

 the larvae at this period of the year. The wild fennel, for 

 instance, absolutely disappears so far as green leaves are con- 

 cerned. It must, therefore, be supposed that the imagines do 

 not oviposit until the autumn, or that the ova do not hatch out 

 until vivified by the autumn rains. In this connection, it is a 

 notable fact that my pupfe of Diloha ccErideocephala, which 

 pupated at the beginning of April, did not emerge until Decem- 

 ber, and then only when damped ; in Central Europe, of course, 

 this species emerges in August. In this case, however, it is 

 desirable to have an observation on the period of emergence in 

 a state of nature, as the time may have been affected by the 

 conditions inseparable with confinement. 



Some evidence as to the manner in which species modify 

 their habits in response to the environment produced by the 

 long spell of dry weather is afforded by the length of time 

 during which most species (and presumably specimens) are on 

 thawing. The life of ix^\ mi\iY\dinQ\ Epinephde jiirtina {ianira) , 

 for example, appears to average about six months, as compared 

 with less than half that period in England. This is, doubtless, 

 of value to the economy of the species, as it is important 

 that the eggs should not be deposited until the autumn, when 

 the young larvse may feed on the fresh vegetation brought 

 forth by the early autumnal rains. Any such modification in 

 length of life, of course, would be of value only to species 

 whose pabulum (c. r/., grasses) is not available as food during 

 the dry weather. Cabbages, for instance, do not dry up very 



