10 NATURAL HISTORY. 



Neuroptera, although the ligula is occasionally cleft in front, the general rule is that the parts of the 

 labium are united in the middle line so closely as entirely to conceal the original constitution of the 

 organ of two lateral halves, so that the labium really approaches that of the Beetles more nearly than 

 that of the Orthoptera. 



The Neuroptera may be characterised generally as rather soft-skinned insects, with a head of 

 small or moderate size, closely applied to the thorax, and having a pair of well-developed compound 

 eyes, and a pair of usually many-jointed, bristle-shaped, or necklace-like antennae, which are sometimes 

 clubbed at the end. The ocelli are frequently wanting. The parts of the mouth are variable in their 

 development ; their characters will be described under the two principal groups into which we 

 divide the order. The prothorax is always free, sometimes ring-like, sometimes considerably 

 developed ; the veins of the wings may be either simple or united by cross-veins ; the 

 tarsi are usually of five joints ; and the abdomen consists of eight or nine segments. In some cases 

 there are tail-like appendages at the extremity of the abdomen, but these, when present, are not 

 jointed organs such as occur in the Orthoptera. 



The Neuroptera have generally a short intestine, usually provided with a sucking stomach, and 

 in many with a globular proventriculus. The Malpighian vessels are long, and from six to eight in 

 number. The females of certain forms are provided with special glands connected with the oviduct, 

 the secretion from which serves to form an envelope for the eggs, or a long stalk upon which they are 

 supported when laid. The larvae are provided with the usual six thoracic legs, and the abdomen in 

 many species bears peculiar appendages which assist the insect in its movements. Many species, in 

 fact the whole of one of the two great divisions, are aquatic in the larval state. The pupa is some- 

 times free, sometimes included in a cocoon spun by the larva. In character it resembles the pupae of 

 the Coleoptera and Hymenoptera, having all the limbs and other appendages enclosed in separate 

 sheaths, and free ; but the pupae of the Neuroptera usually acquire the power of movement just before 

 the emergence of the perfect insect, and this enables them to get into a suitable position for this final 

 change, which is especially important in the case of the aquatic species. 



In their habits the Neuroptera present no special peculiarities. They are generally not 

 particularly active in the perfect state ; some of them fly in the day time, while others are chiefly on 

 the wing in the evening twilight. Some are carnivorous in their habits, whilst others either feed on 

 the nectar of flowers or abstain altogether from food. The larvae of one of the two principal groups 

 are carnivorous, those of the other chiefly herbivorous, although animal food does not come amiss to 

 them. The order is but a small one, the number of known species from all parts of the world 

 probably not greatly exceeding 1,500. 



The geological distribution of the Neuroptera is very difficult to ascertain, owing to the similarity of 

 the wings of these insects, the chief parts preserved, with those of the Orthopterous Pseudoneuroptera, 

 which, as already stated, were formerly included with them in the same order. It would appear, 

 however, that the order is not of ancient date. The Palaeozoic types, which have been described as 

 Neuroptera, seem all to be either Pseudoneuroptera or most nearly allied to that tribe. In the Trias 

 forms which appear to be related to the existing North American genus Cha,ullodes have been met 

 with, and in the Lias and Oolites a few species of different families occiir. In Tertiary deposits they 

 are more plentiful, but the number of recorded fossil species is not great. 



The Neuroptera as here defined are divided into two principal groups (sub-orders). These are : 



I. PLANIPENNIA, having the fore and hind wings similar, usually both in form and structure, the 

 hind wings never broader than the others and folded ; the organs of the mouth fully developed and 

 generally distinct, the mandibles being horny biting organs, the maxillae furnished with two separate 

 lobes, and five- or six-jointed palpi, and the labium generally distinct, with three-jointed palpi ; the 

 prothorax generally well developed, and the other two segments nearly equal. Larvae rarely 

 aquatic. 



II. TRICHOPTERA, with the wings clothed with hairs or hair-like scales, dissimilar, the hinder 

 ones generally wider than the others and folded, the mandibles reduced to mere membranous 

 rudiments, and the maxillae and labium united into one mass, the former having palpi of from two to 

 five joints, and the latter either three-jointed palpi or none at all, the prothorax ring-like, and the 

 mesothorax much larger than the metathorax. Larvae aquatic. 



