14 SPOLIA ZEYLANICA. 
one day, while standing a few yards away from me, he netted a 
male specimen of Appias paulina. Just as he caught it a large fly 
darted upon it, and on examining his capture he found an Asilid 
astride of the butterfly, with its piercing mouth parts buried in the 
thorax. The butterfly was apparently killed immediately, and it 
seems possible that these flies inject some poisonous fluid into their 
prey, which at once renders them inert. Subsequently at Trinco- 
malee I captured, within a few days, Asilids* carrying and devouring 
the following species, all of which were abundant at that time— 
Appias paulina, Catopsilia pyranthe, Junonia lemonias, Terias sp.,+ 
Nacaduba sp. Generally the butterfly was carried with its wings 
apposed, while the Asilid sucked its juices from the side of the 
thorax. From the following evidence I am inclined to believe that 
even the larger and more powerful species are not exempt upon 
occasion from the attacks of these ferocious flies. One afternoon, 
on the road between Trincomalee and Tamblegam, I picked up a 
fresh specimen of Papilio crino, a species of larger size than P. polytes. 
All the juices had been drained out of its body, and this had evidently 
been done quite recently, for it had not had time to get stiff when I 
found it. Moreover, the scales of the fore wing were rubbed sym- 
metrically in a little patch on either side, just where the feet of the 
Asilid would have come had it captured the Papilio in the position 
in which Mr. Dobell’s Appias was captured. The butterfly was 
picked up just at the time when the males of various species, 
including P. crino, were settling on moist or otherwise attractive 
patches by the roadside, and in my own mind I have no doubt but 
that this specimen had been suddenly killed by an Asilid as it 
settled on such a patch, and that, after being sucked dry, it had been 
dropped on the road where I found it. 
Whether Asilids exercise any discrimination with regard to the 
butterflies that they attack is a question which is not easy to answer 
with the little knowledge at present at our disposal. Such evidence 
as exists has recently been brought together by Poulton,{ and even 
among the few cases hitherto recorded there are two in which the 
Asilid preyed upon distasteful species. 
After having repeatedly watched these flies hawking along roads 
and jungle paths near Trincomalee and.elsewhere, I am inclined to 
believe that they swoop at the first butterfly that comes near enough 
to give them a chance of catching it. As they sit watching, as a rule 
on or close to the ground in a sunny place, itis obvious that such 
butterflies as habitually fly high or keep for the most part in the 
jungle are unlikely to be attacked. Since the females of most of 

* The commonest species was Scleropogon piceus (PI. II., fig. 16). For this 
identification I am indebted to my friend Mr. C. Lamb. 
t I took only one Asilid carrying a Lycenid, and this belonged to a smaller 
species than that usually met with. 
{ Trans. Ent. Soc., Lond., 1906. 
