456 THE ZOOLOGIST. 
Mr. J. Jenner Weir mentioned a case of parthenogenesis in Lasiocampa 
quercus, which had recently come under his notice. 
The President read the following letter from Herr A. W. B. Grevelink, 
of the Hague, relating to the insects which attack the cocoa-nut trees in 
the West Indies :— 
“ At Barbadoes the cocoa-nut trees were all destroyed by the Aleyrodes 
cocois, which afterwards, according to Sir Robert Schomburgh, extended its 
ravages over Antigua, Nevis, St. Christopher’s, and other islands, from 
which I infer that it did the same in Martinique, as that island lies in the 
same line with the rest. The year or years, however, in which all this 
happened I have never been able to make out, and all that I can gather on 
this point, from the ‘ History of Barbadoes,’ is that the said trees had been 
planted after the hurricane of 1831, and that they had attained to maturity 
when the insect first showed itself, which, as regards the new plantations, 
cannot well have been earlier than 1837. 
“ Now it so happened that in March of the same year, whilst serving as 
Lieutenant on board H.M. Brig ‘ Echo,’ then stationed in the West Indies, 
I assisted in carrying over from St. Pierre, Martinique, to Curacao a con- 
siderable number of the nopal-plant (Cactus coccinillifera), peopled, of course, - 
by the cochineal insect; and as it was not many months afterwards that, in 
the last-named island, the cocoa-nut trees on some of the estates began to 
show symptoms of being affected as if by blight, which on examination was 
pronounced to be caused by an insect of the Coccide or Coccus genus, 
many persons there have ever since held the opinion that it was introduced 
at the same time with the cochineal from Martinique, which opinion was 
not a little strengthened when, in 1839, tidings from that island stated that 
all the cocoa-nut trees there had been destroyed by an insect (name not 
mentioned), but which, all things considered, I have not the least doubt 
was the same species which ruined the cocoa-nut trees at Barbadoes. 
“ After making a voyage to Europe, I arrived again at Curagao in the 
beginning of September, 1838, where I took charge of the estate St, Joris, 
belonging to my family, on which were about two thousand cocoa-nut trees, 
the greater part of which were then already in a sickly condition, caused 
evidently by a microscopic insect which covered every part of the crown and 
extended also deep down into the heart of the tree, though outwardly the 
stem remained free from them. I applied every means that could tend to 
arrest their progress, in which I persevered during several months, but 
without any perceptible effect, for the fronds turned yellow and dropped to 
the ground as before. Trees which when I arrived were still healthy 
successively caught the infection, their leaves withered, and after they, as 
well as the fruit-stalks, had all dropped, down came also the centre of the 
crown, when nothing remained but the lifeless trunk, a useless encumbrance 
