228 HUBERT M. MORRIS. 



Thorax strongly arched dorsally. Pair of thoracic spiracles slightly projecting 

 laterally. Tibiae and tarsi of fore legs extending from side of eyes level with 

 antennae to anterior margin of second abdominal segment, with tarsi in apposition 

 along median line. Second and third pairs of legs parallel to first, all except tibiae 

 and first and last tarsal segments of second and last tarsal segment of third, covered 

 by wings ; last tarsal segments appearing posterior to those of first leg, and those of 

 each pair in contact along median line. 



Fig. 12. Pupa of Bibio marci, ^, x 5. 



Abdomen nine-segmented; length of segments in proportion 7, 10, 11, 12, 12, 

 11, 10, 9, 9 ; width of segments decreasing gradually towards posterior end. Cuticle 

 with many fine wrinkles, mainly transverse ; on abdominal segments, dorsally 

 and ventrally, bearing numerous spines similar to, but less stout than, those of 

 larva, occurring singly or in groups of two to four, on slight swellings of cuticle. 

 Terminal segment (fig. 13) bluntly conical, bearing a pair of stout, dark brown, 

 sharply pointed processes at the posterior end, directed posteriorly and outwardly, 

 and a pair of rounded papillae. All segments except eighth bearing a pair of slightly 

 projecting spiracles laterally, towards the anterior margin of the segment. 



Fig. 13. Posterior ex- 

 tremity of pupa of Bibio 

 marci, ^ dorsal view, 

 X 18. 



Bibio lacteipennis, Ztt. 



A number of larvae which proved to be those of Bibio lacteipennis, Ztt., were 

 found in a plant pot at Withington, Manchester, during February 1918. The larvae 

 were kept in some of the same soil, which was a rich leaf-mould in which bulbs had 

 been grown, in the laboratory, and the first pupa was seen on 23rd March, and the 

 first adult appeared on 13th April. 



Larva. 



It is proposed to point out the differences between the larva of this species and 

 that of Bibio marci. L., which has been described above. 



The most obvious differences between these two species are the smaller size 

 of the larva of B. lacteipennis and the fact that the processes on its body are 

 relatively more slender. The number and arrangement of the processes on all the 

 segments is the same in both species. 



