IMMATURE SPECIMENS OF PENELLA FILOSA. 



301 



accessory branches and so further approached the complexly- 

 parted appendages of the adult. The dimensions of " E" were; 

 head 3 mm., thorax 150 mm., abdomen 9 mm. The head was 

 2 mm. wide and the horns spread 3.5 mm. The total length of 

 " F " was 133 mm. 



Although fundamentally similar, in several points the develop- 

 ment shown by this series differs from the only previous descrip- 

 tion of undoubted Pendla larvae which I have been able to find, 

 that recorded for P. varians by Steenstrup and Liitken ('61). 

 This earlier account starts with a larva (Fig. 5) unquestionably 

 much more immature than the youngest form in my series. 



FIG. 4. Head of most mature larva of P. filosa ; "F". Anterior and posterior 

 extremities of the abdomen of larva " E ". 



This individual seems to have been about one centimeter in length, 

 was filiform with a highly-convex cephalothorax, succeeded by 

 three short thoracic segments, a long thoracic segment and a 

 short, segmented (?) abdomen. This latter region lacked lateral 

 appendages. The relative proportions of cephalothorax, thorax, 

 and abdomen were 



as shown in the figures 



about i' 4' i' 



