NO. lO MORPHOLOGY OF GNATIIOTRICHUS SCHEDL 83 



THE HEAD 



The elements of the adult and larval head are also recognizable in 

 the pupa. The antennae are among the first parts to be fully developed. 

 The mandibles, the maxilla and the labium are first indicated by low 

 elevations which become gradually the shape of the corresponding 

 elements in the adult stage. A lobe, situated dorsally of each mandi- 

 ble (Ep) is more distinct in the younger pupa and gradually dis- 

 appears. It is apparently the reduced labrum and clypeus. A sirnilar 

 development takes place with the frontal groove which is a distinct 

 wide groove at first and later on becomes reduced to the narrow simple 

 sutura fronto-verticale. The larval setae of the head are all com- 

 pletely lost in the pupa. 



THE THORAX 



ProtJw rax. —The: shape and the relative proportions of the pro- 

 thorax resemble very much that of the adult. The sternum and the 

 extreme anterior margin of the pronotum are more strongly developed 

 at first. The latter is padded at first and densely covered with minute 

 spines. The setae are all lost with the exception of those of the 

 prescutum and the scutum. The setae fi_4 of the prescutum are 

 arranged similarly as in the larva while fs is wadely separated from 

 the rest in the direction toward the caudal margin of the sclerite. 

 The setae scutali Ci-i are, as in the larva, situated in a nearly straight 

 transverse line near the caudad border of the pronotum. The ar- 

 rangement of the setae shows that the pronotum of the adult be- 

 longs with its anterior three-quarters to the prescutum and that only 

 the caudad narrow portion originates from the scutum. The spiracle 

 is plainly visible in the young pupa and becomes covered by the 

 caudad lateral angles of the pronotum. 



Mesothorax. — The mesothorax is somewhat more strongly de- 

 veloped in the pupa than in the adult. The mesonotum is not over- 

 lapped by the pronotum and is present as a nearly rectangular plate 

 extending the full width of the mesothorax. The only setae found 

 were the 63.4 of the larval stage ; they are in a position similar to 

 that in the larva. The elytra are thicker than in the adult, the tra- 

 cheal vein is well developed, and the articulation occurs along their 

 whole bases occupying the greatest part of the pleural area. 



Metathorax. — In the metathorax the scutum with the scutellar 

 groove is first recognizable. The prescutum and the piDStscutellum or 

 postnotum are indicated by two narrow transverse bands only. The 

 scutum bears the setae e3_4 corresponding to the larva. The meta- 



