The locust plague and its suppression / by Æneas Munro.

  • Munro, Aeneas.
Date:
[1899]
Catalogue details

Licence: Public Domain Mark

Credit: The locust plague and its suppression / by Æneas Munro. Source: Wellcome Collection.

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    in one square yard 64,000 larval locusts ! Sometimes, however, disease affects the eggs in a nest, others are liable to be attacked by worms or flies, so that in this case a certain percentage of the eggs are not fertilised, or at all events do not come to maturity—in certain seasons and districts at all events this is the case. The breeding power of insects can be imagined if, as Hader affirms, a single female house-fly produces in one season 20,080,320 eggs ! 116. Insects deposit their eggs variously.—Some eject one at a time, here and there, as if flung carelessly away to take its natural chance ; some do the same with more or less greater design and care; some deposit a number of separate eggs as if in a cluster or group— “ blow-fly ” fashion ; some cover the eggs with body fluff or some sort of glutinous secretion ; some leave the eggs quite exposed ; some care- fully hide or cover them in self-manufactured dung-balls (atenchus); some choose one kind of material and some another in which to deposit them; some require more moisture than others; some do not appear to have any system, while others follow a well-known systematic order. There is observable in this function of insect life an infinite variety. 117. Locusts deposit their eggs methodically.—The laying or depositing of the eggs in the case of the locust is extremely in- teresting and notable. They always follow a definite line or practice, which fortunately may be well observed by any person who will. All the different kinds adopt the same principle. One species may have some minor differences as compared with another. Thus the Cyprian and Rocky Mountain locusts only lay in one nest abput 28 separate eggs, while the migratory locusts, as seen in South and North Africa, Algiers, Egypt, and South America, lay on an average about 80 to 90 (60 to 120). It was noticed, however, that the Cyprian locust laid three times in what may be termed the same season. The same observation has not been made in regard to the migratory locust. Yet, in most other essential points of comparison in regard to laying and nesting, what applies to the one species will hold good also of the rest, with, so far as I know, this single trifling exception, namely, that the nests of the migratory locust are straight, and not curved like those of the Rocky Mountain locust. The eggs in all are placed in a slanting or oblique direction, and arranged after exactly the same pattern, somewhat as the grains are formed, as already indicated, in a bere or barley ear. This general plan may be seen more or less in the accompanying Fig. 7. 118. Labour saved and the orderly exit of the young secured.—Even the most casual observer cannot fail in noting that the female locust takes great pains to arrange the eggs in her own special and particular fashion, and no doubt there are special objects to be derived if we can only interpret them correctly. There are some 4
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