INSECTS 



viviparous brood acquire many shades of green or reddish-brown colour. 

 This species possesses both winged and apterous males. 



The sycamore and the maple trees form food for Drepanosipbum 

 platanoides and Chaitophorus aceris. The latter insect is interesting from 

 its dimorphism. Occasionally it produces, in addition to the normal 

 progeny, a curious toad-like form which has puzzled entomologists both 

 as to its family and species. Under the name of Phyllophorus testudinatus 

 it was thought to be the larva of some unknown insect. Subsequently it 

 has proved to be an aberrant form of one of the green viviparous females 

 of Chaitophorus aceris. These singular abortions, if they may be so called, 

 are found slowly crawling in the condition of small yellow scales under 

 the leaves. The body, legs and antenna? are furnished with folioles or 

 flabellas. They are quite solitary, isolated in habit, and never develop 

 any sexual organs, though they may persist for four or more months 

 without leaving the leaves from which they suck the sap. They never 

 develop wings, but they cast their integuments as delicate membranous 

 sloughs. Though this insect has been several times described, it still 

 forms material for the expert microscopist to work out its morphology 

 and embryology. 



Aphides and galls. The obscure cause of the mimicry of the natural 

 fruits of plants by insect agency is open to speculation and is full of 

 interest. A good example of such is to be found in the false cones of 

 the spruce fir, which are so remarkably similar to the true cones of that 

 fir as to be scarcely distinguishable from them. On opening one of such 

 cones we find the chambers to be tenanted by hundreds of the winged 

 and oviparous females of Cbermes abietis. The delicate winged forms of 

 these flies are often to be seen flitting above the openings of these cones 

 on sunny days. Several galls on the oaks, made by Gynipidce, are also 

 partially tenanted by aphides, but the species, I believe, is not well identi- 

 fied. Erect, pedunculated galls are also found on the upper surfaces of 

 elm leaves ; these are the work of Tetraneura ulmi. But perhaps the 

 most remarkable gall, also on the elm, is made by Schizoneura lanuginosa. 

 These galls are very like unripe figs, and measure as much as three inches 

 in length. They open from the top, out of which issue thousands of the 

 winged forms which have been bred from the apterous grubs within. 

 Our poplars are visited by several species of aphides, each of which 

 makes its own peculiar gall. These may be instanced by Pemphigus 

 bursarius^ P. spirotheca and others. It is interesting to note that such 

 galls are duly represented by structures on the native poplar trees found 

 on the plains of Afghanistan. Some aphides are the prey of Diodontus, 

 Coryna and Psen, all of which are minute Hymenoptera. The last-named 

 insect carries live aphides to chambers hollowed out of the pith of the 

 blackberry. These aphides are consumed by the larvae afterwards 

 hatched from the ova of the Psen. 



Before concluding this brief account of the Homopterous Aphididae^ 

 some remarks may be added as to the underground forms which affect 

 ants' nests. The solicitude of these interesting Hymenoptera for the 



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