HETERoMORPHA. 



3G3 



Siphonaptera. The larva is limbless, has biting mouth-parts, and consists 

 of a head and twelve more or less similar segments. It has ten pairs of stigmata 

 on the three thoracic and the seven anterior abdominal segments. The pupa 

 is free-limbed. The month-parts and the form of the body resemble those of 

 the imago : it lies in a cocoon. 



Coleoptera. Many Coleopteran larvae are Campodeiform. They have three 

 well-developed pairs of limbs on the thoracic segments and, at the end of the 

 abdomen, in many cases, there is a pair of filamentous or stylet-shaped appen- 

 dages. More frequently a pair of truncated prolegs is found at the posterior 

 end of the body. The head, which is always well developed, shows the fork- 

 line mentioned in connection with the Lepidoptera, and carries antennae, which 

 are usually short, and a variable number of ocelli (six or fewer) on each side ; 

 these, however, are often wanting. The mouth-parts are adapted for biting, 

 the mandibles are, in individual cases (Dyliseidae), changed into sucking 

 organs. There are generally nine pairs of stigmata, the first of which occurs 

 on the first or second thoracic segment, or on the boundary between the two, 

 while the others belong 

 to the first eight ab- 

 dominal segments. The 

 aquatic larvae (Lytiscus, 

 Hydrophilus) are meta- 

 pneustic, some having 

 tracheal gills (Gyrinus). 

 The body may be elon- 

 gated as in the thread- 

 like larva of the Elaler- 

 idae; in other cases, it 

 broadens out into a shape 

 resembling the Isopoda 

 {Parnidae). TheLamelli- 

 corn larvae are eyeless, 

 soft-skinned, and whitish 

 in colour, and are further 

 distinguished by the sac- 

 like enlargement of the last ring of the body [Rhizotrogus). In forms which 

 bore their way into wood or under the bark of trees, the limbs are vestigial 

 or are altogether wanting (Buprestidae, Cerambycidae). Such degenerate larval 

 forms may finally become maggot-like ( ( 'ureulionidch , Bostrychidae). 



The pupa is free-limbed, and resembles the imago in the form of the body 

 and in the structure of the mouth-parts. 



A complicated metamorphosis, named by Fabre (No. 105) hyper-metamor- 

 phosis, is undergone by the Meloidae in adaptation to the peculiar manner of 

 life of the larva. The young is at first an active Campodeiform larva (Fig. 

 180 A), which attaches itself at the first opportunity to the male of Anthophora, 

 and, during copulation, passes over to the female. As soon as the host has 

 laid its eggs in the cell prepared for them in the earth and filled with honey, 

 the Sitaris larva takes possession of the cell, devours the egg, and subsequently 

 lives upon the honey. Here it moults and passes into a stage in which it can 

 only move slightly, and is maggot -like with educed limbs (Fig. ISO B). 

 It then changes into a pseudo-chrysalis (Fig. ISO C), a quiescent, pupa like 

 stage. From the pseudo-chrysalis there emerges first a larva resembling the 



Fig. ISO.— Metamorphosis of Sitaris (after Fabre, from 

 Lcbbock). A, first larval stage. C, second larval stage. 

 C. third larval stage (so-called pseudo-chrysalis) D, fourth 

 larval stage. E, pupa. 



