21 



male are black, with parts slightly tawny. Those of the 

 female are testaceous. In the male the body is long and 

 narrow with longitudinal spots on the back, and the eyes nearly 

 meet ; while the body of the female is much broader, the spots 

 or lines, on the back are indistinct, and the eyes are far apart, with 

 a white border around them (Fig 3 a.). The flies appear first 

 in March. There are several broods of flies during the spring and 

 summer, the number depending upon the weather and the state of 

 the plants. Eggs, white, oval, with pretty markings which can 

 be seen with a good pocket lens, rather more than half a milli- 

 metre in length, are laid in groups of from two to seven on the 

 under surfaces of the leaves. As many as forty eggs were found 

 on one leaf in July last. Larvae, or maggots, come from the eggs 

 in about eight days, and immediately bore into the leaf, getting 

 out of sight as quickly as possible. The maggot (Fig 3 c.) is about 

 the third of an inch in length, without feet, yellowish white, but 

 with green colour in the intestinal canal showing plainly through 

 the skin after it is a few days old. It is cut square at the tail end, 

 but its he id is sharply pointed, being furnished, as Westwood 

 describes it, " with a corneous instrument in the shape of S, 

 " which moves round a small fixed point, enabling them to scrape 

 " up the soft parenchyma of the leaf." If the maggot is watched 

 under a strong glass its head will be seen to move with a rapid cir- 

 cular motion, scooping out the leaf tissues, and feeding with won- 

 derful voracity. It took a full-sized maggot just five minutes to 

 bury itself completely in a fresh leaf upon which it was placed, 

 For about 28 days the larva feeds, and then pupates either in the 

 ground or upon the leaves. Many pupae were found on the leaves 

 in July and August last. The pupa is of a reddish colour, and 

 about the fourth of an inch long (Fig. 3 d). From pupae I kept 

 in a glass case flies came in 1 1 days, but they did not lay eggs 

 in confinement, though fresh leaves were constantly supplied. 



METHODS OF PREVENTION AND REMEDIES. 



Syringing the plants with solutions of soft soap and quassia 

 directly the first signs of the attack are visible, makes the 

 leaves unpleasant for the maggots, and prevents them from 

 getting in to the tissues, just as syringing hop plants with this 

 mixture either prevents the winged aphis from remaining on the 

 leaves and depositing her young, or the young aphides from 

 feeding on them. From five to six pounds of soft soap and the 

 extract of nine to ten pounds of quassia should be used to 100 

 gallons of water and put on well under the leaves by means of a 

 " Knapsack " machine, or a Strawsonizer. 



Carbolic acid, or paraffin, may be used with soft soap instead 

 of quassia, in the proportion of three to four quarts to 100 

 gallons of water. This mixture should be prepared with very hoi 

 water and kept well stirred It should be understood that the 

 soft soap is mainly useful in fixing the unpleasant materials 

 upon the leaves. 



