206 DISEASES OF INSECTS. 
tells us % follows, when the same experiment is re- 
peated on the workers or drones : they immediately be- 
come unable to take any further part in the labours of 
the hive; they can no longer guide themselves except in 
the light ; if they petition one of their fellow-citizens for 
honey, they are unable to direct their tongue to its mouth 
to receive it ; they remain near the entrance of the hive, 
and when the light is intercepted they rush out of it to 
return no more. 
Insects occasionally are subject to tumours or a preter- 
natural enlargement of their parts and organs. The an- 
tennas of bees sometimes swell at their extremity so as 
to resemble the bud of a flower ready to open, becom- 
ing at the same time very yellow, as does the fore part 
of the head b . I once saw a specimen of a Hi/d robins — 
agreeing with II. fuscipes in every other respect even to 
the most minute punctum — which had a large tumour 
on each side of the prothorax, evidently accidental, occa- 
sioned probably by the stoppage of the pores by which 
the superfluous moisture and air escape when it under- 
goes its last change. The converse of this I have ob- 
served to take place sometimes in the same part of Geo- 
trupes foveatus, the ordinary lateral fovcce becoming very 
considerably enlarged ; — this was the case with the spe- 
cimen from which Mr. Marsh am made his description 
of that insect. The species is, however, very distinct in 
other respects, and may always be known by its small 
size. It happens now and then also, that these tumours 
represent blisters. I saw one once on one elytrum of a 
beetle and not on the other. Those of Scrropalpus (as 
3 Huber AbeUles ii. 409. " X. Did. d'His't. Xat. i. 42. 
