22 NATURAL HISTORY. 



Proctotrypidce. These lay their eggs (one or more, according to the species) in those of 

 Lepidoptera or other insects, and the larvae which issue from them speedily devour the contents. 



If the evolved larva has escaped this danger, it gnaws its way out of its shell, and not 

 unfrequently devours the remainder before tasting other food. In this second stage of its existence 

 the insect is generally of a cylindrical shape, and is composed of thirteen joints, which are called 

 " segments," and are more or less distinctly separated from each other. The head forms the first 

 segment It is always well marked, and is of a bony consistence, much harder than the rest of the 



body. The upper part consists of two lobes, separated above 

 by a longitudinal division. The upper part of the face is 

 called the clypeus, or shield, which varies in shape in different 

 species, and below this is the upper lip, or labrum. Six 

 very minute ocelli, stemmata, or simple eyes, as they are 

 variously called, are arranged in a semicircle on each side the 

 mouth.* Below the labrum are the mandibles, and it is 

 worthy of notice that although Lepidoptera are haustellate, 

 or sucking insects in the perfect state, they are always mandi- 

 bulate in the larva. The antennae are small, pointed, movable 

 projections, placed at the base of the mandibles. They are 

 generally four-jointed. Beneath the mandibles are a pair of 

 lower jaws (maxillae), which are soft and membranous, and 

 fitted for holding rather than biting their food. They are 



MOUTH OF LABVA OF THE PRIVET HAWK . . . 



MOTH. iurnisned with two small four-jointed organs, called maxillary 



o. upper Lip; ^M^ndibies: c, jaws; d, Lower Lip; palpi, and behind these parts is situated the membranous 



lower lip, or labium, below and on the inside of which are 



two small two-jointed organs, called labial palpi. At the extremity of the labium is situated a 

 conical jointed projection, called the spinneret, from whence issue the threads used by the larva in 

 the construction of its cocoon, and in the case of some gregarious species, its nest. 



The twelve, segments forming the body of the larva are covered with a soft flexible skin, which 

 may be either smooth, granulated, hairy, or spiny. The three segments behind the head which corre- 

 spond to the thorax of the perfect insect are each furnished with a pair of true legs, consisting of 

 three cylindrical joints, covered by a horny skin, and terminated by a claw. In some species, as in 

 the larva of the Lobster Moth (Stauropus fagi), these legs are of extraordinary length. If one or 

 more of these legs should be amputated, the corresponding leg of the imago will also be more or less 

 defective. There is often a horny plate on the back of the second segment behind the head, which is 

 called the scutellum, and there is a triangular flap on the last segment, above the anus, which is often 

 horny, and is called the abdominal fold. Each segment, except the first, third, fourth, and last, is 

 provided with a small opening on each side, above the feet, which is surrounded by a horny margin. 

 These openings are the spiracles, through which the insect breathes, and they are generally placed 

 on round coloured spots, called stigmata. Those on the second and twelfth segments are the largest. 



Besides the six true legs, the larvae of Lepidoptera are furnished with from one to four pairs of 

 fleshy " pro-legs " on segments 7 10, and an additional pair, called " claspers," which terminate the 

 last segment. No European larva has more than sixteen legs, but the larvae of some American Bom- 

 byces are said to have twenty, segments 6 11 inclusive being furnished with pro-legs. On the other 

 hand, the larvae of the Geometridce have only ten legs, those on segments 7 9 being obsolete. 

 Those of the Nepticulidce have nine pairs of ill-developed pro-legs, but no true legs, and those of the 

 Limacodidce are entirely footless. 



The pro-legs consist of two fleshy joints, and are adapted for climbing. In the case of larvae 

 which live exposed they are rough at the extremity, and furnished with a circle of small hooks 

 directed inwards ; but in those which live inside the stems of plants they are smooth, and provided 

 with hooks directed outwards. In many Notodontidce the claspers are replaced by two long slender 

 appendages, which sometimes enclose retractile filaments, as in the larva of the Puss Moth (Centra 

 vinula); and in the Drepanulidce the last segment terminates in a double point. 



* Six is the usual number on each side in the larvae of Lepidoptera, but it is not invariable. 



