16 THE entomologist's RECORD. 



IX. Silk-spinninii habit. — This vai'ies with the foodplant ; on Ptelea 

 — a tree — the young larvfe spin noticeably more silk than they do 

 when feeding on the lower Skmnna bushes. I suppose because on the 

 fluttering leaves of the Ptelea they need a firmer foothold in the wind. 

 Again, when resting or feeding upon fennel-plants, they seem to spin 

 no silk at all, except when about to undergo ecdysis, perhaps because 

 the slender and rounded leaves of the fennel afford them a sufficiently 

 secure position without having to attach themselves to anything else. 

 The larva appears to spin a certain, though variable, amount of silk 

 when changing its skin, but not always otherwise. The adult larva 

 only spins silk when undergoing ecdysis. 



X. Miscellaneous {cryptic effects, etc.). — (1) When young the larva 

 of P. niachann seems to rely for protection against its enemies 

 almost entirely on cryptic eftects, when older on effects that are- 

 cryptic, but warning, when it is discovered. At first it resembles a 

 minute speck of black, and, as is well-known, a little later on it 

 assumes that saddle-marking of so many Papilionid larvae which 

 imitates a bird-dropping. Later on, it becomes a singularly con- 

 spicuous object when removed from its foodplant and placed amid 

 other surroundings, but one which is easily passed over at a casual 

 glance when resting or feeding amongst the bright green leaves. A good 

 reason for supposing that the markings of P. machaon are cryptic as well 

 as warning, in its latest larval stage, is that I have noticed that the 

 larvae feeding on fennel have a habit of ascending to the flower-heads 

 of that plant when full-grown, where they are much more difficult to- 

 see than when amongst the plumy leaf -manes. Then the bird- 

 dropping markings of P. machaon may serve a double purpose, as I have 

 noticed that the larv;e feeding on the seed-pods of Dictaninus are much 

 lighter in colour (indeed, they closely resemble the light brown-green 

 ground colour of the pods) than those feeding on Skimmio, etc. 



(2) The larva of P. machaon, in its last stadium, exhibits great 

 variability both in the size and colour of its markings. The green 

 ground colour, the black bands, and the red spots being different in 

 tone and in extent in almost each individual. 



(3) The larvae of P. machaon, in many cases, extrude their osmateria 

 less readily when full-grown. Some, indeed, refused to do so at all, 

 though subjected to much rough handling, whilst others would do sa 

 readily, even when suspended for pupation. As regards the 

 pupating-habit, there appear to be two distinct strains in our English 

 P. wacliaon, some (about a third) remaining sluggish till the last, and 

 pupating either almost in sitii of their feeding-ground upon the young 

 stems of the SA-n».»(/rt bushes or lower down beneath the branches; 

 whilst others will wander a considerable distance in search of a suit- 

 able spot. I have noticed that those which pupate more than a foot 

 from the ground, unless when hidden amongst the bushes, are in- 

 variably stung by the small ichneumon which infests P. machaon. This 

 year, out of about a hundred pupaj which I found under the wooden 

 framework, etc., of my butterliy-house not one had escaped. I have 

 many small deciduous trees growing in my butterfly-house, but I have 

 never found a P. machaon pupa amongst the leaves of these, I suppose, 

 because in Avinter a green pupa on a bare twig w'ould be a conspicuous 

 object to birds, though in summer it would be well protected by the 

 leaves from the attacks of ichneumons. I think that perhaps this is a 



