INSECTS AFFECTING PARK AND WOODLAND TREES 



323 



anal fork black tipped. Thoracic feet blackish, marked witli black. Body 

 unicolorous, immaculate, or the orange spots of the next stage partly 

 present (another brood). 



4th statre. Head shining; black, thi: front with four grooves and two 

 dents above the clypeus ; sutures around the mouth brown; width 1.4 mm. 

 Thoracic feet large, pale olive, 

 marked with black ; abdominal 

 ones small, on joints 6-1 i, 13, pale 

 green. Body smooth, irregularly 

 5-annulate, the creases like slight 

 folds ; shining blackish, olivaceous, 

 with a series of lateral pale orange 

 spots, distinct only centrally. The 

 spots are above the subventral fold 

 on annulates 2 and 3. 



Larvae vary in shade, some 

 are blacker than others, and the 

 orange spots vary in distinctness. 

 The larvae scratch the leaf with 

 their anal prongs and make a rasp- 

 ing sound. 



5th stage. Width of head 

 1. 4- 1. 6 mm. As before, slaty 

 black, except the feet ; lateral 

 orange patches on joints 3-12; 

 the two median annulates have 

 somewhat corneous, dorsal, trans- 

 verse areas, shining, but concolor- 

 ous with body. Feet all pale watery. Two days after molting the larvae 

 began to turn shining and livid and with a pale dorsal streak anteriorly and 

 entered the ground to spin their cocoons. 



The adult insect is brownish, black, marked with yellowish white and 

 measures about '3' inch in length. 



Life history. The first indications of the presence of these slugs on 



willow, according to L)r Howard, is seen in peculiar ])listerlikt- swellings on 



the upper surface of the foliage, which sometimes give it a wa\y or 



crumijled appearance. Investigation shows that these swellings are occa- 



sionetl 1)\- the presence of o\al, wliitisli eggs partially inserted in the unde-r 



surface of the leaf substance. Black spots and streaks appear about the 



time hatching begins, four to eight days after oviposition, the effect of 



