260 INSECTS AFFECTING VEGETATION 



The female lays from 300 to 500 eggs, depositing them in a 

 mass beneath the tip of the abdomen, and covering them with cot- 

 tony wax filaments. As the mass of eggs increases in size, owing to 

 the deposition of more eggs, twenty to thirty being deposited every 

 twenty-four hours, the body of the female is gradually tipped up- 

 ward, until it finally assumes a position almost perpendicular to the 

 surface of the leaf or twig. Egg depositing continues for from a week 

 to ten days, and when it is finished nothing is left of the insect except 

 a shrunken and dried-up skin. The eggs hatch in about two weeks 

 from time of deposition, those first laid hatching first, so that there is 

 a difference of several days in the ages of the Iarva3 from the same 

 batch of eggs. The larvae resemble the adults in appearance, except 

 that, when first hatched, they are quite small, and not covered with 

 the white, waxy filaments. They remain in the mass of waxy secre- 

 tion with which the egg mass was covered for several days before 

 crawling out upon the plant to begin feeding. Owing to the differ- 

 ence in time of hatching of the eggs, considerable difference is no- 

 ticed in the size of the larvae from the same batch of eggs, and it is 

 usually possible to find insects of all sizes and ages upon the plant at 

 any time. Their development is rather slow, it requiring about six 

 weeks to two months for them to reach the adult. Most of this time 

 is spent on the underside of the leaves, sucking the juices from the 

 plant by means of a slender sucking tuibe, which is inserted into the 

 tissue along the midrib and veins. 



A few weeks after the eggs have hatched small masses of the 

 filamentous matter will be noticed on the under side of the leaves, 

 usually a short distance from the veins of the leaf. These are the 

 pupae of the males. The males are small, winged insects, very slow 

 and awkward in their flight, and not readily observed, because of 

 their color, which is a kind of olive brown. They appear and mate 

 with the females when the latter are about half grown. Of greenhouse 

 plante, the coleus geranium and sago palm seem to be its favorite 

 food plants, but it is often found on many others. 



The Long-spined Mealy Bug. This species of mealy bug, as has 

 been said, while quite common in Maryland greenhouses, does not 

 seem to be as abundant as P. citri. It is readily distinguished from 

 that species by the length of the spines at the anal extremity of the 

 body, the last two of which are as long as, and sometimes longer, 

 than the body. In its life history and habits it is so nearly identical 

 with the foregoing species as to render unnecessary any separate treat- 

 ment, while its food plants are fully as numerous, and many of them 

 the same. (Bui. 119, Md. Agr. Exp. Sta.) 



The Black Scale. This is another very widely distributed scale, 

 being found in nearly all parts of the world. In the warmer cli- 

 mates it infests outdoor plants, but in our latitude, and throughout 

 most of the United States, it occurs only as a greenhouse pest. It is 

 not particularly destructive, but often occurs in great numbers, and 

 always accompanied by a black fungus, which lives upon the honey 

 dew excreted by the insects, thus rendering the attacked plant very 

 unsightly in appearance. 



