ANNULOSA: INSECTA. 355 



or even spin cocoons. In one section of the Diptera, hence 

 termed Pupipara, the larvae continue to reside within the 

 mother until they are just ready to become pupae, and they 

 are born in a form closely resembling the ordinary pupae of the 

 members of the order. In the Hessian Fly (Cecidomyia) the 

 larva produces asexually a number of secondary larvae, which 

 are developed within the body of the primitive larva, and feed 

 upon its tissues, ultimately causing its death. 



The Diptera constitute one of the largest of the orders of 

 the Insecta. Amongst the more important forms included in 

 this division may be enumerated the House-flies, Bluebottles, 

 and Flesh-flies (Musddce) ; the Gnats, Midges, and Mosquitos 

 (Culicida)', the Bot-flies (Ofstrida}; the Gad-flies (Tabanida) ; 

 the Forest-flies and Sheep-ticks (Hippobosdda) ; and the Crane- 

 flies (TipulidcB). 



ORDER X. LEPIDOPTERA. Mouth suctorial, consisting of a 

 spiral trunk or " antlia" composed of the greatly-elongated maxilla, 

 and protected, when not in use, by the cushion-shaped hairy labial 

 palpi. Maxilla forming two sub-cylindrical tubes, united together 

 by inosculating hooks, and constituting an intermediate tube by their 

 junction. Maxillary palpi minute; labrum and mandibles rudi- 

 mentary. Head, thorax, and abdomen more or less covered with 

 hair. Wings, four in number, covered ivith modified hairs or 

 scales ; wanting in the females of a few species. Neruures not 

 very numerous, mostly longitudinal. Antennce composed of numer- 

 ous minute joints. 



This well-known and most beautiful of all the orders of 

 Insects comprises the Butterflies (fig. 189) and the Moths (fig. 

 190) ; the former being diurnal in their habits, the latter mostly 

 crepuscular or nocturnal. 



The larvae of Lepidoptera (fig. 189), commonly called "cater- 

 pillars," are vermiform in shape, normally composed of thirteen 

 segments, the first of which forms a distinct horny head, with 

 antennae, jaws, and usually simple eyes. The mouth of the 

 caterpillar, unlike that of the perfect insect, is formed for mas- 

 tication. The labium, also, is provided with a tubular organ 

 the " spinneret " which communicates with two internal 

 glands, the functions of which are to furnish the silk, whereby 

 the animal constructs its ordinary abode or spins its cocoon. 

 The viscera are embedded in a largely developed fatty tissue 

 (epiploon), which is absorbed by the pupa during its period of 

 quiescence. The three segments behind the head correspond 

 with the prothorax, mesothorax, and metathorax of the perfect 

 insect, and each carries a pair of jointed walking-legs. Besides 

 these thoracic legs, there is a variable number (generally five 



