THE THREE-LINED LEAF-BEETLE: THE LARVA. 



133 



This insect was received from Clyde, N. Y., in the month of July, as 

 quite destructive in potato fields. They were apparently increasing very 

 rapidly from the many clusters of the egg (twenty or more in the cluster, 

 laid upon the leaves. 



This species has long been numbered among the many insects inju- 

 rious to the potato, and is one of those that feed upon it in both its 

 larval and perfect stages. It sometimes occurs in sufficient numbers to 

 be very destructive in New York and the eastern States, while proving 

 comparatively harmless elsewhere. In portions of New York, it has 

 been reported as destroying the potato vines for successive years {Prac- 

 tical Entomologist, i, 1866, p. 113). It was quite abundant in the cen- 

 tral counties of the State in the year 1864, and, from being regarded as 

 a new enemy, much alarm was excited, from apprehension of its con- 

 tinued increase (Fitch, 10th Report, p. 441). In several localities in 

 the Provinces of Ontario and Quebec it is reported as having inflicted 

 an unusual amount of damage among field potatoes {Report Entoniolog. 

 Sac. Ontario for 187 1, p. 67). 



The Larva. 



The larva has the peculiarity of covering its body with its excrements, 



its vent being conveniently located 

 for that purpose upon the upper side 

 lof its terminal joint, as shown at h in 

 Fig. 32. As the material is discharged, 

 it rests upon the surface, while suc- 

 cessive discharges force it forward to- 

 ward the head until the entire back is 

 covered with it, as in the side view of 

 the full-grown larva at a, in the figure. 

 FiG.32.-Theprco-iined Leaf-b.otio,LF.Mri^i- The covering probably serves the 



i.imeata: «, the larva; 6, Its teriiiinal Joints; c, the ox J 



pupa; rf, the eggs. purpose of hiding it from its enemies, 



and perhaps of making it distasteful to birds which would otherwise 

 ])rey upon it. 



In addition to the figure of the larva given, but a few words need be 

 added in description. It is a soft slug-like creature of the general char- 

 acter of the well-known larva of the Colorado potato-beetle. It is trans- 

 versely wrinkled, with a line of rounded tubercles upon the sides, low 

 down. Its color is dull yellow when young, changing to brighter 

 yellow as it matures. The head is of about the size of the first 

 segment of the body, flattened, smooth and black. The adjoining seg- 

 ment is also black. The body is oval, becoming quite thick behind its 

 middle, and very convex on the back. The three pairs of legs on the 

 first three joints are shining black. Behind these upon other joints are 



