158 THE EARLY STAGES OF TABANID^ 



Synchronous with the primary contraction of the segments, a light 

 pea-green suffuses the last three segments of the body. The re- 

 mainder of the larva changes to this color over night. By morning 

 the abdominal segments have changed from green to ocher, when 

 the molting of the cuticle ensues. The shedding takes place in sec- 

 tions. 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 loosened on the side opposite that to which the chitinous framework 

 of the head is attached. This is shed by a peculiar auger-like move- 

 ment of the tail end which is not attached to the glass or other ob- 

 ject 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 anchor- 

 age during the remainder of the ecdysis. 



The upper half of the body of the newly molted larva is encased 

 as in an armor in pouches and pads of integument, outlining in a 

 gauzy film the future appendages of the fly. 



Mitzmain's description of the full grown larva (Plate 5, Fig. 80, 

 c) is given below: 



"The length is 28 to 29.5 mm.; the width, 3 to 4 mm. 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 sup- 

 ports 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 four black, me- 

 dium-thick, skeletal pieces running the length of the three cephaHc 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 [Plate 5, Fig. 79] are heavy, powerful structures, slightly ser- 

 rated on their inner surfaces. The musculature of these appendages permits the 



