ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
33 
The various stages through which the insect passes, in the passage from 
the egg to the mature form, differ somewhat in the two sexes. In the 
female the eggs, which are found massed together under the scale, give 
rise to minute larvae ; these are provided with three pairs of legs and a 
pair of antennae, together with well- developed mouth-appendages which 
form the rostrum. They move actively about in search of a convenient 
place of fixation. This is effected by the larva inserting its rostrum into 
the tissues of its host, when it sucks up the nutritive juices of the plant. 
Soon after fixing itself the larva casts its skin, and by so doing loses botli 
legs and antennsB ; it thus becomes fixed for life on the spot where it 
first took up its position. The larval skin is not entirely thrown off, 
but remains covering the insect, and forming the scale, shield, or 
puparium ; the secretion from the spinnerets which serves to keep the 
cast skin in its place is much less than in allied species. Later on the 
insect undergoes a second and final moult. The skin thus thrown off 
is added to the first, and the insect lies as a motionless mass covered in 
by the two larval skins, which form the scale of the adult female. The 
female is probably fertilized soon after the second moult, and its body 
becomes swollen with eggs ; these are deposited under it, and the body of 
the mother collapses and dries up. The early stages in the male — egg, 
larva, and first moult — resemble closely the similar stages in the female. 
But legs, wings, and antennas are, later on, developed, and from the 
pupa a winged adult is produced. The posterior pair of wings are 
replaced by halteres, which resemble similar structures among the 
Diptera. The abdomen is produced into a long process or style, which 
forms the external organ of reproduction. During their metamorphosis 
the males lose their mouth-parts, and their short life is entirely devoted 
to fertilizing the females. 
The following scheme shows the life-history of this insect : — 
Mobile larva Mobile larva 
I I 
Small round scale Small oval scale 
I I 
Large scale Pupa 
Winged Insect 
I 
Egg- 
Honey-dew.* — Herr M. Btisgen has made an elaborate study of 
honey-dew. He begins with a historical account of the opinions men 
have held in regard to it. Pliny and many later observers said that it 
fell from heaven ; many botanists regarded it as an exudation from the 
plants ; many zoologists referred it altogether to the Aphides. Now it 
is commonly believed that there are two kinds — an animal honey-dew and 
* Jenaisclie Zeitsehr. f. Naturwiss., xxv. (1891) pp. 339 428 (2 pis) 
1892. D 
