466 JOURNAL, BOMBAY NATURAL HIST. SOCIETY, Vol. XXV. 



The Larva. 



The young larva on first emergence is enveloped in a filmy skin but this 

 is thrown oft' as soon as it arrives in the water. Pierre describes one 

 particular species which as soon as it hatches out from the eggs (these 

 being deposited on the stems of osiers, some distance above water level) 

 by a sharp curving or bending of the body, leaps clear of the woody stem 

 and generally falls into the water where it floats belly upwards. Should it 

 however fall on to the muddy foreshore, it will continue to leap about by 

 the same curious contractions of the body until it has made its way down 

 and into the water. The duration of the first instar is said to be extremely 

 short, varying between a few seconds to a few minutes but the subsequent 

 instars of which there are from 11 to 15 are of a much longer duration, some 

 of the later ones lasting for several months. The larval stages are prolonged 

 over a period of a minimum duration of ten months up to a maximum of 

 five years. 



The young larvte live in the interstices of water- weed, preferably 

 in masses of spirogyra or in shallow runlets overlaid by curtains of 

 the same weed. The Libellulines are nearly always found in such 

 situations but as they grow to adult size, they become more bold and may 

 then be seen moving stealthily over the bottoms of deep pools. The 

 Zygopterygine larvre prefer more open situations such as the borders of 

 tanks or streams, where they may be found clinging to the stems of 

 submerged reeds or water-weed. 



The larvie of Dragonflies, even in the same genera to a slight extent, are 

 polymorphic but broad differences are only found when comparing the 

 forms of the different families. They may be divided up into several 

 classes according to the shape of their labium but it will be more convenient 

 here to describe them under the same divisions as the imagines. 



The Auisopteridie larvre (Plates X and XI). 



Roughly one of these larvte may be said to consist of the same parts as 

 does the imago, if we except the wings, anal appendages, and the sexual 

 organs. There is, however, a great difference in the shape of the individual 

 parts and the prothorax and thorax form one solid, fused mass. 



The head is much smaller than in the imago, somewhat quadrilateral in 

 the Libellulines, Aeschnines, Cordulines and a few of the larger Gomphines 

 but more conical as a rule in the latter. It is provided with two large 

 compound eyes, which again, are much smaller than in the imago, and which 

 are invariably well separated. They may form the whole of the side of the 

 head or be confined to the outer and anterior angle only. The eyes maj^ 

 be flat, or rounded, entire or crossed b}'- sutures or their central part raised 

 in a papilliform eminence. In addition to the latter, there are three access- 

 ory eyes or ocelli as found in the imago, which are more perfectly developed 

 in some species than in others and which may be, in some, almost obsolete. 

 The ocelli may be mounted on a vesicle or lie flush with the surface between 

 and just in front or behind the eyes proper, and it is very doubtful from 

 their appearance as to whether they functionate mthe larva or not. To the 

 inner side and in front of the eyes will be found the antennse. They jjossess 

 a much higher development in the larva than in the imago and the segmenta- 

 tion is much more evident, the number of the latter being as a rule, about six. 



The mouth is situated on the under side of the head and is furnished with 

 a pair of very massive jaws which are concealed by a jointed, mask-like 

 labium, the "mask." This latter structure is one of the most interesting 

 features found in Dragonflies and is quite Tinique amongst insects. (Plate 

 XII.) The mask shows considerable differences in shape according to the 

 species, that of the Libellulines being broad, cupped, somewhat foliate and 

 bearing a row of long, imbricated spines, or interlocking teeth along the 



