[...]... wingless, and in others wing length varies between the sexes Stick insects are slow-moving, herbivorous and mostly nocturnal Their shape and cryptic coloring make them very difficult to see among foliage and affords them protection from predators Some species freeze motionless when disturbed, holding the middle and hindlegs along the body and stretching out the front legs, while others sway to imitate the. .. to the thorax by a flexible, membranous neck It bears the mouthparts, comprising the labrum, mandibles, maxillae and labium, and also the antennae, compound eyes and ocelli On the outside it is marked by grooves, most of which indicate ridges on the inside; some of these inflexions extend deep into the head, fusing with each other to form an internal skeleton These structures serve to strengthen the. .. small hooks called hamuli The order is divided into two suborders, the Symphyta (sawflies) and the Apocrita (wasps, ants and bees) Sawflies have herbivorous larvae and the adults do not have a constricted waist The females have a saw-like ovipositor for laying eggs into plant tissue In the Apocrita, the first segment of the abdomen is fused to the thorax and the second, and sometimes the third, abdominal segments... CHAPMANSIMPSONANDDOUGLAS Date:19/9/12 Time:15:39:43 Page Number: 11 PREFACE Reginald Chapman’s The Insects: Structure and Function has been the preeminent textbook for insect physiologists for the past 43 years (since the moon landing, in fact) For generations of students, teachers and researchers The Insects has provided the conceptual framework explaining how insects work Without this book, the lives... ganglion (see Chapter 20) They are often called the gnathal segments because their appendages form the mouthparts of the insect The pre-oral segments are innervated by the brain, but their nature and number remains contentious The protocerebrum (forebrain) innervates the compound eyes, the deutocerebrum (midbrain) innervates the antennae, and the labrum receives its innervation from the tritocerebrum (hindbrain)... Name: CHAPMANSIMPSONANDDOUGLAS 1 Head REVISED AND UPDATED BY STEPHEN J SIMPSON INTRODUCTION Insects and other arthropods are built up on a segmental plan, and their characteristic feature is a hard, jointed exoskeleton The cuticle, which forms the exoskeleton, is continuous over the whole of the outside of the body and consists of a series of hard plates, the sclerites, joined to each other by flexible... small in size and have a complex nervous system surrounded by an effective blood– brain barrier Insects were the first creatures to take to the air and have prodigious reproductive rates These factors, together with the complex interactions they have with other organisms, have led to their great success both in terms of species richness and abundance The very high diversity of insects today is the result... mantids to calculate the distance of their prey using triangulation The coxa of the front legs is very elongate and the femur is enlarged and equipped with rows of sharp spines and teeth The tibia, which is also spined or toothed, folds back on the inner face of the femur like a jack knife The strike, which takes place in two phases, lasts less than 100 milliseconds In the initial phase, the tibiae are fully... divisions The mayflies (Ephemeroptera), comprising . CHAPMANSIMPSONANDDOUGLAS Date:19/9/12 Time:15:39:30 Page Number: 1 The Insects Structure and Function FIFTH EDITION The Insects has been the standard textbook in the field since the first edition. the Pancrustacea (Fig. 1). The mandibles of these two groups have similar origins, and the development of the nervous system is similar, as is the structure and wiring of the compound eyes. A little. discrete functional units, of which the most universal is the head. Besides the head there may be a trunk, as in the Myriapoda, or a separate thorax and abdomen as in the Crustacea and Hexapoda. Based