210 The Philippine Journal of Science isu 



ocher, when the molting of the cuticle ensues. The shedding 

 takes place in sections. The chitinous framework of the head 

 is thrown off like a hood. This portion is everted upon the 

 body, and remains dangling from the exuvia during the process. 

 One-half the length of the skin is loosed on the side opposite to 

 that to which the chitinous framework of the head is attached. 

 This is shed by a peculiar auger-like movement of the tail end 

 which is not attached to the glass or other object in the container, 

 as in the previous molts. The skin is virtually unrolled from 

 the detached head to the anal end, where it lies in a crumpled 

 heap. Then the skin of the other side of the body begins to be 

 shed. The chitinous framework constituting the former head 

 capsule of the larva becomes rolled up in the exuvia, while the 

 skin is torn slowly from the new membrane. When the first 

 half of the skin is peeled off to the anal tip, the cast skin becomes 

 attached to some object. In this instance the glass of the jar 

 served as an anchorage during the remainder of the ecdysis. 



The upper half of the body of the newly molted larva is en- 

 cased as in an armor in pouches and pads of integument, out- 

 lining in a gauzy film the future appendages of the fly. 



GENERAL DESCRIPTION OF THE FULL-GROWN LARVA 



The length is 28 to 29.5 millimeters; the width, 3 to 4 milli- 

 meters. The anterior half of the body is a greenish yellow, 

 the remainder is a dirty white. At this stage the form is 

 grub-like. 



The head capsule, which occupies one-fifth the length of 

 the larva, is a cylindrical bulb, formed by the invagination 

 of the thoracic ectoderm. It supports the eyes, the antennae, and 

 the mouth parts. It is bound by a framework of chitinous rods, 

 the cephalopharyngeal apophyses. This structure, observed 

 through the thorax when the insect is in action, is composed of 

 4 black, medium-thick skeletal pieces running the length of the 

 3 cephalic segments in the form of a pyramid, with its apex 

 provided with the external mouth parts. It terminates in the 

 claw-like mandibles which are similar in color and texture. 



The mandibles are heavy, powerful structures, slightly ser- 

 rated on their inner surfaces. The musculature of these appen- 

 dages permits the two elements working in apposition. At 

 rest they are held horizontally, and can be projected suddenly 

 and thrust vertically downward, which is obviously of great 

 assistance in grasping the prey. 



