137 
the base, leaving no indication of the exact point.’’ In pairing, 
the male “runs backward and forward over the back of the female, 
seeming to stroke the head and antennae with his own with a 
jerky motion, when he will at once run back and attempt to cop¬ 
ulate, but if the female is not in the desired position, he will run 
forward along her back and go thru the same maneuvers. On the 
morning of May 30 they appeared to have finished their work of 
pairing and ovipositing, and both sexes were found seemingly 
nearly dead in the bottom of the cage.” 
Remedial Measures .—The most efficient and economical known 
means of keeping this orchid Isosoma in check is fumigation once 
a week with one of the nicotine extracts, to kill the “flies.” This 
method, however, can not be practiced when the flowers are in 
blossom, for a strength which will kill the adults is likely to in¬ 
jure the delicate flowers. 
Cutting off and destroying infested bulbs is the method most 
commonly adopted by florists, and it will, in time, if persistently 
practised, eradicate the pest; but this measure may prove expen¬ 
sive because of the great value of the flowers, and altho infested 
bulbs will never flower, it is often difficult to detect them, and one 
will sometimes sacrifice a good flower-bulb by mistake. The plants 
should be examined regularly once a week for infested bulbs. 
It has been suggested by M. Gazagnaire*, who, with M. Kunckel 
d'Herculais studied this injury to orchids in greeenhouses in Paris, 
that the larva could be killed by inserting a triangular dissecting 
pin into various parts of the gall-like swelling, the supposition 
being that the pin will pierce the larva and cause its death. If, 
however, the larva is present, it will already have destroyed the 
embryo flower-bud, and if, by mistake, an uninfested bulb is thus 
pierced, the flower-bud is likely to be ruined, so it will probably 
be better to adopt the method of cutting off and destroying the 
bulbs supposed to be infested, as above recommended, for besides 
being easier it will beyond a doubt destroy the insect—a result 
which can not be certainly counted on if the needle method is used. 
Decaux, in the article cited on page 136, has suggested the in¬ 
jection of carbon bisulfid or nicotine into the infested bulbs; but 
this is open to the same objection as is the remedy suggested by 
M. Gazagnaire. 
In obtaining stock it should be subjected to the most careful 
inspection, to make sure that it is not infested. 
The three following pests have been noticed doing more or 
less damage to greenhouse plants, and altho not insects they may 
profitably be treated in this connection. 
*Ann. Soc. Ent. de France, 1888, Bull., p. XXITT. 
