42 THE CAUSES WHICH PROPAGATE 



the continuation of this transitory sleep, participated in by many 

 wasps, bees, and our own domestic flies, which in October resort 

 to coigne and crevices, or the Shard-born Beetles {Geotrupes), who 

 then bury themselves in the ground, thereby showing protection 

 is conjointly connived at. It is also no less remarkable that the 

 most sensibly lethargic Lepidoptera, as the Peacocks, Admirals, 

 Tiger Moths, and Burnets are likewise most conspicuous from 

 beautiful colour. 



Muscular contractions on touch or sight, accompanied by 

 emission of liquids or odours from secretory glands, likewise 

 indicate fear. The larvte or grubs of certain beetles when thus 

 stimulated drop saliva, or exude volatile fluids from two or more 

 dorsal tiibes; in the case of the Red Poplar Beetle {Una 

 tremula) smelling of naphtha, while those of the Stag Beetles 

 strongly savour of guano. In certain lepidopterous caterpillars, 

 as those of the genera Danais and Papilio, these scent-tubes are 

 protrusible. The secretion of the caterpillar of the common 

 Swallow-tail Butterfly, redolent of pine-apple or fennel, is given 

 off powerfully when by pressure between the finger and thumb 

 it is induced to protrude its forked excretory tentacle from the 

 second segment ; and that of its congener Podalirkis emits under 

 similar circumstances a scent which has been compared to that of ripe 

 pears. The caterpillar of the Puss Moth we find even attributed 

 with a voluntary power of communicating electi'icity. A corre- 

 spondent to the Magazine of Natural History relates, " On 

 being taken from a young pojilar the Cerura showed decided 

 symptoms of irritation, which particularly drew my attention. 

 It began to contract its body, drawing itself closely together, 

 and by degrees elevated and extended its bifurcated tail. Then 

 were slowly protruded from out of the points bright red fila- 

 ments, and irregularly bent to one side. In a short time I 

 felt a sudden tingle along my arms, which made me stop 

 with surprise, and shortly another shock, which made me 

 almost involuntarily throw the twig with the creature upon 

 the ground/' The larvse of the genus Porthesia have two 

 ordinary sac-like tubercles, one on either of the penultimate 

 segments. The very beautiful scarlet-lined caterpillar of the 

 common Gold-tail Moth [Auriflua) , has these tubercles con- 

 tractile, and above perforated by a keyhole-shaped opening, 



