ENTOMOLOGY 157 



pears after the middle of June, and early crops hence escape their 

 ravages. 



Eggs are probably deposited, as a rule, on the fruit, blossoms or 

 foliage, and the young larvae soon begin to feed. The life cycle re- 

 quires about twenty-seven days, and several broods occur each season. 

 The winter is past in the pupa state in the dead cucurbit leaves, and 

 trash in and around the field. About seven months of the life of the 

 insect seems to be passed in the pupa state. 



The most hopeful method of protecting cantaloupes from this 

 insect, that we have discovered, is in the use of squash plants as a trap 

 crop. A decided preference seems to be shown for the bloom, vines 

 and fruit of squash, which should be planted in and around canta- 

 loupe fields, and the larvae carefully collected and destroyed. Arsen- 

 ites and repellants have not thus far proven to be effective. 



Melon-Louse on Cucumber. At all times after cucumbers com- 

 mence to "run" they are subject to attack by a plant-louse. The in- 

 sect is blackish-green in color and both winged and wingless forms 

 occur. They multiply so rapidly as almost to cover the under sides 

 of the leaves in a short time. Ordinarily in large fields, the attack 

 commences in certain small, well-defined areas, from which the 

 trouble spreads rapidly in ever widening circles rendered conspic- 

 uous by the curled and discolored leaves. The source of the pests was 

 for some time a mystery, but Mr. Theodore Pergande, of our Na- 

 tional Bureau of Entomology, throws a great deal of light on the sub- 

 ject when he explains that the same insect feeds also on cotton, 

 orange, melons, strawberry as well as on a long list of our common 

 weeds. In the light of this information, it is easy to see how the 

 pest is kept alive until opportunity to attack melons and cucumbers 

 offers itself. 



The fact that the pests work almost entirely on the undersides 

 of the leaves, where it is difficult to apply sprays, makes ihem very 

 serious pests to combat. The writer has made an effort to select a 

 spray that will kill the greatest number of those hit, trusting to the 

 operator to hit as many as possible and to repeat the application when 

 necessary. Others have found it practical to place a low tent over 

 the plants, and to fumigate with burning tobacco stems and other 

 agents. Such fumigation has given partial success, but seemingly 

 is little, if at all, superior to the sprays. The cost of fumigation is 

 unquestionably greater. The spray tnat gave the best results with 

 us was whale-oil soap kerosene-emulsion, with Pyrethrum added. 

 (See directions for preparing insecticides.) This was diluted ten 

 times. We succeeded in killing about 99 per cent of the lice, in one 

 trial, doubtless all that were hit. In order to apply this spray with 

 sufficient thoroughness, a knap-sack pump was used. This was fitted 

 with a short extension, about three feet long with a Vermorel nozzle 

 set at right angles to the extension, making it easy to apply the spray 

 sidewise and upward from beneath. 



As stated, the lice usually start from one or two vines in a field. 

 Careful watching will reveal these centers of infestation and prompt 

 treatment should check their spread in the beginning. Of course it 



