80 Orthonhaplia liiachycera. 



dorsal surface six, on the ventral surface two bristles, and one on 

 each side margin; besides these therc are some smaller bristles. On 

 the anterior margin of sonie of the ventral segments tliere is a trans- 

 verse row of small warts; the last segment has the anus as a longi- 

 tudinal split on the ventral surface, and in front of it a transverse 

 row of short spines, directed backwards; at the apex the segment has 

 a swelling with a transverse, terminal, spiracular split, and to eacli 

 side of it a small spine: the segment has on the margin four bristles. 

 The larva is generally considered as amphipneustic. as it has pro- 

 thoracic and terminal spiracles, but I detected on the first seven 

 abdominal segments very small and indistinct spiracular piates, lying 

 on each side of the segments, somewhat inwardly lo the base of the 

 lateral bristle; these spiracles are certainly not in function. The small 

 papillæ mentioned by Austen (Ann. Mag. Nat. Hist. 7, III, 1899. 185). 

 certainly have nothing to do with spiracles, such papilla-likc folds are 

 fmind in severa! larvæ of Stratiomyids. — The skin of the larva is 

 of the same leathery consistence as in the Stratiomyids and shows a 

 similar structure. It is covered with oval or circular scales of calcareous 

 matter, easily seen with a lens; the calcareous particles are not nail- 

 shaped, as in the Stratiomyids, but plate-shaped. and do not reach far 

 inwards. The skin bubbles strongly when laid in chloric acid. — The 

 length of the larva is about 16 mm. The pupa has a thinner skin 

 than that of Xylophagus ; it has no spines between the antennæ; the 

 abdominal segments, except the first and the last, have on the dorsal 

 side, at the posterior margin, a transverse row of strong, very close 

 standing, brown bristles, on the ventral side there are none; the 

 apical segment terminates in two small lobes. There are prothoracic 

 and seven pairs of abdominal spiracles. The length of the pupa is 

 about 13 mm. 



The pupa rests in the rigid larval skin, when emerging the skin 

 splits with a transverse split at the suture between the pro- and 

 mesothoracic segments, a similar split in the second abdominal segment 

 and a longitudinal split between these; then the pupa works out, until 

 only a part of the abdomen is in the larval skin. and Ihe imagu then 

 escapes, leaving the pupal skin sticking in the puparium formed by 

 the larval skin. 



The larvæ live in decaying wood in old trees, especially in 

 beech. oak, alder, poplar, horse-chestnut and maple, and they 

 feed on the decaying matter. They libernate and develop in 

 summer. 



The species of Xylomyia occur in woods and are especially found 

 on stems with decaying parts; they are not very lively. 



