264 MR. R, SHELFORD ON MIMETIC INSECTS AND [ Nov. 4, 
also made use of by several species of Calobata and allied genera, 
but in the case here deseribed the mimicry of an Ichneumon-fly 
is carried still further, inasmuch as the coloration is almost 
identical in both species, viz., black with yellow spots on the head 
and thorax, with alternate yellow bands on the abdomen, while 
the legs are ochreous with a black band at the apex o the 
femora and tibie. Furthermore, the ample clear wings are very 
similar in both mimic and model (compare figs. 5 & 6, Plate XXIT.). 
The nearest allies of this remarkable fly occur in S. America. 
Mimic. ? Vylophagus sp. (Fam. Leptide.) Plate XXIT. fig. 8. 
Model. Jesostenus sp. Plate XXII. fig. 7 
This example is remarkable for the great elongation of the 
antenne of the fly. In the previous case it was seen that the 
long antennze of the model were represented by the fore legs of 
the mimic, but here there is an actual copy produced by means 
of a very unusual modification amongst the Diptera. The 
mimicry is so perfect that it will almost bear a close scrutiny 
through a lens; the large eyes, prominent clypeus, and maxillary 
palps ‘of the fly give the head, even when thus closely examined, 
a characteristic Hy menopterous appearance. For the rest, the 
coloration is almost identical in both species: black with yellow 
spots and bands (compare figs. 7 & 8, Plate XXIT.). The larva of 
the fly was found im decayed wood and presented no very extra- 
ordinary features. 
viii. Mimic. Sepedon sp. near javanicus (Desv.). (Fam. Scio- 
myzide.) Plate XXIT. fig. 4. 
Model. Collyris emarginata (Macl.). Plate XXII. fig. 3. 
It is not usual to find amongst the Diptera species which 
minue any other order of insects than the Hymenoptera. This 
example anda species of Celyphus, which only very doubtfully 
can be considered as mimicking a small bug, are the only cases 
known to me. 
Both of the species now under discussion were caught together 
on the wing on Mt. Serambu, Sarawak, and when seen alive and 
actively moving about were not readily distinguishable. As 
cabinet specimens they furnish an imstance of the importance of 
field-work in the study of mimicry, and of the unreliability of 
dead impaled insects or mere figures unless, indeed, both are 
prepared with reference to careful observations of the living 
forms. ‘The fly when alive was of a very brillant blue like that 
of the Collyris, but the colour has now faded to a dusky indigo, 
while the abdomen being much shrunk detracts considerably 
from the previous resemblanc e. The legs are brilliant red, and 
constituted one of the most conspicuous fe: tures of both fly and 
heetle (compare ft igs. 3s 4 Plate NOSE.) 
>i 
