58 NATURAL ARRANGEMENT OF INSECTS. 



found their representatives among the Annulosa, our 

 theory on the natural system would be but an idle spe- 

 culation; and our first proposition that one uniform 

 plan reigned throughout nature would be denied. That 

 the reader, however, may have this remarkable fact 

 brought before him, we shall first proceed to describe 

 what, in our opinion, are the primary forms of larvae, 

 and the series in which they naturally stand; and we 

 shall then test the whole by comparing them with the 

 vertebrate series of forms as defined in our former 

 volumes. As the larvae of many natural groups in this 

 class of animals are either unknown or imperfectly un- 

 derstood, we shall select those belonging to the diurnal 

 butterflies (Papiliones Sw.) ; because they have more 

 especiallly engaged the attention of entomologists; and 

 because their forms, with a few exceptions, are the best 

 known. At the same time, we wish it to be understood 

 that the following remarks, so far as our own investi- 

 gations have extended, are more or less applicable to 

 the chief groups of the Annulosa. 



(54.) It appears to us that nearly all larvae may be 

 referred to some one or other of the following types, we 

 shall designate by these names : 1 . The luliform, or 

 pre-eminently typical, 2. The Raptorial, or sub-ty- 

 pical. 3. The Natatorial, or Anopluriform. 4. The 

 Suctorial, or Vermiform, called also the Onisciform: 

 and, 5. The Rasorial, or Thysanuriform. The first two 

 of these belong to the two typical groups, and the last 

 three to the aberrant group. Let us now proceed to 

 notice them more particularly in the same order. 



(55.) The luliform type of larva stands at the 

 head : it is so called because of its resemblance to those 

 insects which constitute the perfection of apterous in- 

 sects, and of which the common ringworm (lulus), so 

 frequent under stones and bark in this country, is a 

 good example. Caterpillars of this type are always 

 smooth; they have no horns or excrescences either upon 

 their head or their skin: they possess no noxious qua- 

 lity; nor do they assume, when disturbed, any threatening 



